Global Trends in Preschool Literacy (PL) Based on Bibliometric Analysis: Progress and Prospects

Abstract

Preschool literacy (PL) is a critical period in the development of children’s literacy skills, which has a significant impact on their reading ability and academic achievement. In this context, there is a fragmentation of knowledge as PL involves different disciplines such as education, psychology, and linguistics. This is despite the existence of a large body of literature on PL. However, many studies focus on specific topics, which makes it difficult for researchers to gain a comprehensive understanding of the current status, research hotspots, and trends in PL research, leaving a knowledge gap. Therefore, this study adopts a quantitative research approach for the literature data between 1992 and 2022 for a period of thirty years. This study used arithmetic in Microsoft Excel and bibliometric visualization tools, including VOSviewer and Biblioshiny. The aim was to analyze the current situation, trends, and future development of literacy at the preschool level, providing a scientific basis for preschool practice and policy development. An analysis was performed on 1208 screened documents from the Scopus database in Excel, resulting in the identification of annual publication trends, the 20 most cited documents, the 15 most productive authors, the top 10 institutions, and the 20 countries with the highest number of publications. Visual collaborative networks and co-occurrence analysis maps via VOSviewer and Bibliometrix were also conducted. The study found that the number of research papers published on PL has shown a steadily increasing trend, that the United States is a pioneer in the field of preschool literacy and is increasingly collaborating and researching with other countries, and that international connections are growing between publications and authors. Furthermore, preschool institutions, teachers, and families have positive attitudes towards preschool literacy, as reflected in theoretical research, teaching practice, and sustainable knowledge construction. Meanwhile, the findings of this study also revealed that new PL research has been extended to emerging literacy skills, family-based literacy models, and literacy intervention models. Future researchers can benefit from this study by increasing collaborative research that can sustainably add to the body of knowledge and improving the sustainability of PL.

1. Introduction

Preschool literacy (PL) is considered a precursor to the development of traditional forms of reading and writing in the preschool years, including phonological awareness, letter and sound knowledge, and oral language [1]. The literacy of preschool children is the foundation for children’s academic success [2]. Increasingly, preschool policymakers, administrators, researchers, and early childhood teachers are being given the responsibility of ensuring the quality of preschool education, especially in the areas of language and literacy [3]. Numerous studies have revealed that children’s early literacy and language development are closely related to the presence of proficient reading and writing in later years [1,4]. In fact, children who enter kindergarten with relatively low literacy skills are more likely to struggle with immediate or long-term reading development [1]. Such a process may lead to the Matthew effect [5], in which weak literacy skills hinder learning in other academic areas. Therefore, one should try different approaches to promote children’s literacy skills. In addition, the home learning environment and preschool programs have an important impact on preschoolers’ literacy. Some findings indicate that this effect persists after several years, although it decreases after entering elementary school [6].

In recent decades, the area of PL has attracted many educational practitioners and academics who have taken great interest in studying children’s language, reading, and writing [7,8,9], as well as discussing the role of home and school environments in children’s literacy in depth [10,11]. Nonetheless, questions are beginning to emerge about how to teach literacy in preschool, how to create sustainable learning environments, how to develop indicators of early literacy, and how to effectively help children learn [12,13]. It has been argued that children in the preschool years are more likely to develop interest and positive attitudes through play and interaction rather than being introduced to formalized literacy instruction too early [14]. Others believe that PL is an important early education task and that educators should provide appropriate literacy activities and materials to promote children’s letter awareness and reading readiness [15]. They have explored more practical ways to promote the effectiveness of children’s literacy instruction and verify the positive impact of literacy on preschoolers’ literacy learning [16].

Current research on PL has also begun to map emerging trends and developments in early childhood literacy learning, particularly the impact of early inhibitory control skills on literacy development and the effectiveness of home-based literacy intervention on literacy skills [17,18]. It can be said that research on PL has produced some results. However, several questions remain unanswered: What is the main research focus of PL at present? What is its current status and trend? In addition, there are few in-depth and systematic visualizations of the research results in the field of PL. This leads to several problems: (i) It hinders the clarification of the current PL research review and the further improvement of the overall research system. (ii) It is not conducive for researchers to keep track of current research progress and prevents researchers from keeping abreast of the latest research topics.

The purpose of this study is to provide an overview of the current state of the art in the area of preschoolers’ early reading and to suggest future research possibilities. To summarize the results of previous studies and give an overview of the state of the field, most studies have focused on either systematic analysis or meta-analysis [19,20]. In general, systematic analysis has a limited number of studies, while meta-analysis focuses on homogeneous results or data from several studies studying the same issue [21]. However, in the field of PL, it is necessary to study the current situation and future trends. In this regard, this study applies a bibliometric approach, which is a quantitative analysis of the characteristics and statistics of the literature to reveal the relationships among the literature, the trends in the research field, and the metrics of academic influence [22]. The reason behind this is that the information in the literature on PL can be processed and sorted out from several perspectives and levels with the help of calculations and analysis. This allows for the effective presentation of the development of PL in the discipline of preschool education. Furthermore, it is possible to explore the nature and potential research directions that exist within it. The bibliometric approach adopted in this study uses Microsoft Excel data statistics and visualization tools such as VOSviewer and Bibliometrix to conduct a comprehensive and integrated study. Based on the results, relevant publications on PL and the distribution of patterns within a given period are described and in turn compliment these insights. It is also possible to identify emerging PL and future research trends in PL to provide more valuable results and discussions that contribute to existing knowledge. In this study, the following research questions (RQs) will be focused on:

RQ 1: What are the publishing trends in preschool literacy (PL) studies?

RQ 2: Which are the most productive and influential authors, institutions, and countries in the study of preschool literacy (PL)?

RQ 3: What are the knowledge structures presented in preschool literacy (PL) studies in terms of collaboration and co-occurrence networks?

RQ 4: What are the most prevalent themes of preschool literacy (PL) among scholars?

The following sections of this paper are structured as follows: Section 2 is the review of the literature that provides an in-depth examination of literacy and its evolution in preschool children. Specific research methods regarding the bibliometric analysis are presented in Section 3. Section 4 presents the findings and analysis of the study. Section 5 presents a discussion addressing the four research questions. In Section 6, the bibliometric study of PL is summarized, and recommendations for future research are provided.

2. Literature Review

2.1. Literacy and Evolution in Preschool Children

Literacy involves listening, speaking, reading, and writing, which are integrated oral and written activities [23]. Early literacy refers to the skills, knowledge, and attitudes that precede conventional forms of reading and writing [24]. Likewise, literacy is considered a critical skill for individuals in the identification, comprehension, interpretation, communication, computation, and use of written and printed materials [17]. For literacy, researchers have different definitions and theoretical perspectives, largely adapted to national or international needs [25]. In the 21st century, under the impact of information technology, the meaning and interpretation of literacy have expanded significantly, and literacy goes beyond reading, writing, and numeracy skills [26].

Preschool is a crucial stage before entering elementary school. In fact, literacy skills should be developed during the preschool years in the following aspects: firstly, comprehension and use of spoken language, phonological awareness, and vocabulary; secondly, early knowledge about written language, letter writing, and pronunciation. In addition, it involves preschool teachers’ attitudes and experiences with various literacy activities [1,24,27]. As research continues, PL skills are sometimes referred to as emergent literacy skills, early literacy skills, predictive skills, decoding skills, and skills such as comprehension of reading materials [23,28].

Literacy is an essential part of the overall development of preschool children. Since 1946, UNESCO has played an important role in increasing global literacy rates and has promoted literacy efforts in various countries. Subsequently, researchers have explored PL from a wide range of perspectives. Early studies focused on early literacy measures [29] and validated the role of literacy skills in reading at different ages [30]. The study was then further developed to reflect the influence of socioeconomic status, family environment, and culture on literacy in children. For instance, one researcher examined how mothers in Chinese and American families support the literacy development of young children in their daily interactions [31], indicating that early childhood educators must understand the specific meanings of early literacy in different cultural contexts to maximize the learning potential of each child in the early childhood education setting. Thus, educational practitioners’ as well as family members’ perceptions of literacy skills reflect the place of literacy in society.

In addition, there are also findings that suggest four popular themes related to PL research: the home literacy environment, assessment of literacy skills, emergent literacy interventions, and the relationship between literacy and reading [32,33]. This highlights future research in PL review studies, such as the application of literacy learning web technologies, increased interaction, and specific investigations of improved literacy assessment models. This is due to the direct link between literacy concepts and twenty-first-century skills [34]. In addition, recent research by Schachter and Rachel [35] emphasizes the focus on high-quality development of preschool literacy, as highlighted by the relationship between early childhood teachers’ understanding of knowledge and literacy instruction. Academics also realize the need to enhance literacy learning opportunities, and increasing young children’s access to resources and learning opportunities is a joint effort involving educators, society, and families [36]. Literacy in preschool children is considered a key component in improving language development and cognitive skills [37]. Increasing the opportunities and quality of literacy for preschoolers will help children transition from kindergarten to elementary school environments with a sense of adjustment and belonging [38].

2.2. Past Studies and Future Research Pathway

The analysis of specific document sources, citations, keyword networks, institutions, and document types allows for a detailed description of an emerging field. Prior research has often relied on experiments or investigations to assess the important role of PL in early education, including the effectiveness of literacy skills in post-school reading and writing learning [9,39]. In response, there is a need to identify an appropriate approach that can summarize and evaluate the place of PL in early education and identify pathways for future research.

Previous research has typically relied on systematic analysis or meta-analysis, with studies exploring literacy skills solely from the socio-educational domain [26,40]. While systematic analysis is an important tool for summarizing the existing literature, it is restricted by the amount of literature under study. To gain insight into the development of the topic, a meta-analysis or bibliometric analysis with a broader perspective is more appropriate. Specifically, a meta-analysis summarizes existing research and focuses on the combined estimation of effect sizes from multiple independent studies [41]; for example, 48 quasi-experimental studies were analyzed to determine the impact of family literacy programs on the emerging literacy skills of children from low-socioeconomic-status families [41]. Thus, this form of analysis supports studies in which multiple studies on the same issue are usually the subject, but if the purpose of a study is to gain a broader research perspective, such as understanding how research on preschool children’s literacy has evolved over time, it cannot be accomplished by a meta-analysis.

In contrast, this study answers multiple research questions through a bibliometric approach that not only considers emergent literacy skills but also broadens the perspective of preschool children’s literacy. Further research should also consider longer time periods and richer studies, such as different languages and different publication methods, as suggested in existing studies on this topic. By examining the metadata of the papers, it is possible to provide future researchers with more detailed information about the development of any topic of interest. Within this context, the importance of literacy skills in preschool education is emphasized, which calls for a more detailed analysis of PL [36,42].

In summary, it can be concluded that a systematic review is a high-quality, rigorous evaluation and analysis of a specific topic applicable to a specific field of study. A meta-analysis uses systematic data collection and analysis to examine a specific topic. Bibliometric analysis, on the other hand, focuses on a quantitative and comprehensive body of knowledge that can better determine the current state of research and provide a roadmap for further research.

Table 1. Summary of Previous Studies Related to Literacy (TDE: Total documents examined).

Type	Authors	Time Period	TDE	Attributes Examined
Systematic Review	Dere and Ateş [26]	1996–2020	114	With the increased digitization of society and the development of distance learning, media literacy and data literacy will be inevitable in the future.
	Marinelli et al. [40]	2007–2022	6	The results suggest that training should focus on improving basic literacy skills, such as spelling and text comprehension.
Meta-Analysis	Savva et al. [43]	2018–2021	73	The results showed that e-book reading improves literacy skills (vocabulary learning).
	Fikrat-Wevers et al. [41]	1990–2018	48	The study included unpublished research and dissertations and used more rigorous criteria and a larger sample size. More useful conclusions were drawn for shared reading interventions to promote children’s literacy.
Systematic Review and Meta-Analysis	Wang et al. [44]	2008–2021	22	The systematic review aimed to enrich the methodology used in the study, and the meta-analysis provided a comprehensive assessment of the evidence.

lists the forms of analysis that have been used by different researchers in previous studies on the topic of literacy.

3. Materials and Methods

3.1. Data Source

This bibliometric study examined publications in the Scopus database. The Scopus database was chosen at this stage of the study; it is considered that the Scopus platform is considered by researchers to provide the most extensive interdisciplinary abstract and citation database and the largest database of abstracts and citations of peer-reviewed literature covering a wide range of topics. Therefore, the database is also used to cover a wider range of topics [45] and provide the most extensive interdisciplinary abstract and citation database [46,47,48]. Moreover, according to Scopus’ Content Coverage Guide (version 2020), there are 77 million article records in the Scopus database from journals, books and serials, conference proceedings, and trade publications. In addition, Scopus allows further access to data, previews of abstracts, analysis of search results, and more in the search. Scopus has two search modes, one basic and the other advanced. The advanced search enables nesting with the help of Boolean operators (AND, OR, AND NOT) in search and field labels [46]. It is certain that the Scopus database has advantages in terms of quality standards, wide coverage of information collection, etc. [49]. Therefore, this database provides a comprehensive overview of the world’s scientific research results and is appropriate for the needs of this study.

3.2. Search Strategy

The overall search strategy was divided into four steps. First, the search focused on the topic “Preschool Literacy (PL)”; then, the search in Scopus was conducted with partial qualification of the results; by reading the abstracts, the selected documents were ranked one by one to see if they were needed for this study, and thereby the most relevant and clean data were obtained. Figure 1 illustrates the steps involved in obtaining the data for this study.

Specifically, the questions were better explained and responded to by bibliometric analysis based on the four research questions identified. As of April 2023, data obtained from the Scopus database were used, and bibliometric analyses were undertaken. The search term “preschool AND literacy” included in the article title was used to search for articles published in any language related to it. This study is emphasized in the title of the article, as this is the most intuitive representation of the field of study and the topics related to the significance of the study. According to Chamorro-Padial et al. [50], the title is sufficient to allow the reader to assess the article substantively. Therefore, a title-only search strategy was used in this study, thus ensuring that the content searched was as relevant as possible to PL.

Based on the keyword and search strings, search engines retrieve the relevant articles. The search string arrangement respected technical standards by using “quotation marks”, OR, AND, and preparing keywords and synonyms as shown in

Table 2. Search keywords and synonyms in Scopus.

Word	Synonyms
Preschool	pre-school, preschool education, pre-primary education, pre-primary, early childhood, early childhood education, kindergarten, infant education, nursery school, pre-k education, pre-elementary education, young children
Literacy	reading and writing ability, reading, and writing skills, literate competency, reading and writing proficiency, word recognition, knowledge of literacy, literal literacy, emergent literacy

.

The specific retrieval contents were as follows: (TITLE (preschool OR pre-school OR “preschool education” OR “pre-primary education” OR “pre-primary” OR “early childhood” OR “early childhood education” OR kindergarten OR “infant education” OR “nursery school” OR “pre-k education” OR “pre-elementary education” OR “young children”) AND (literacy OR “reading and writing ability” OR “reading and writing skills” OR “literate competency” OR “reading and writing proficiency” OR “word recognition” OR “knowledge of literacy” OR “literal literacy” OR “emergent literacy”)).

The search results showed a total of 1309 documents. To retain documents relevant to the current research topic, various limitations were applied. The search was refined to the complete three decades of publication years from 1992 to 2022, and documents from 2023 (n = 38) and documents from 1963–1991 (n = 27) were excluded for better identification of the development process of PL research and dissection of the latest trends. It is worth noting that documents at the publication stage of Article in Press (n = 27) were not included in this study, at which point the number of documents was 1216. In addition, document types with erratum (n = 8) were also excluded to avoid duplication or miscalculation of documents. The final number as a result of screening was 1208. Figure 2 illustrates the search strategy of this study and presents the data screening procedure.

3.3. Data Analysis Methods

The bibliometric analysis approach is used to highlight research progress, results obtained from previous studies, and gaps and recent trends in the literature [51]. Prior to data analysis, the screened papers were used to describe publication trends within the PL field, using the research question as a benchmark (RQ1). The authors, institutions, and countries that contribute high numbers of publications (RQ2); the prevalent themes and keywords of interest to researchers (RQ3); and the intellectual structure of the components (RQ4) were also analyzed. A bibliometric analysis of all the documents was conducted in terms of specific information presentation. This study utilized the following:

• Analytical functions and tools of the Scopus database to implement some of the content.
• Microsoft Excel to perform mathematical calculations to generate tabular information on the age, frequency, and percentage of published material.
• Publish and Perish software to evaluate the impact and performance of the publications.
• Two free applications for visual analysis: one is VOSviewer (version 1.6.19(0)) and the other is Bibliometrix (bibliometric quantitative analysis software based on the R statistical programming language [52]). Both applications allow collaborations and networks to be effectively analyzed, allowing the specific implementation of, e.g., author relationship maps, co-citation maps, and co-occurrence maps. Thus, the mapping and visualization of bibliometric networks were performed.

All the analysis tools were used to help answer the research questions and contribute to the mapping of the knowledge structure of PL in this study.

4. Results and Analysis

4.1. Descriptive Analysis

This section discusses an overview of research on literacy at the preschool level, including publication sources over a thirty-year period from 1992 to 2022, with 1208 documents retrieved from the Scopus database. In this section, basic publication information, annual publication trends, highly cited documents, and the most productive top-tier authors, institutions, and countries are discussed in detail.

4.1.1. Basic Information

According to the original search in Scopus, the earliest documented paper on preschool literacy (PL) is an article from 1963, focusing on visual-orienting behavior [53]. The subsequent 28-year period (until 1991) also included only 27 publications in total. However, over the next three decades, the number of publications increased significantly at a compound annual growth rate of 13.62%. Therefore, the data after cleaning and screening will first be evaluated according to the type and source of the documents. In this bibliometric analysis, the document types covered are Article, Book Chapter, Review, Conference Paper, Book, Editorial, and Note. The source types of these documents, namely Journal, Book (series), Conference Proceeding, and Trade Journal, are also distinguished.

Table 3. Document Types, Source Types, and Languages of Documents in PL (PL = Preschool Literacy; TP = Total Publications; % = Percentage).

Document Type	TP	%
Article	951	78.73
Book Chapter	131	10.84
Review	54	4.47
Conference Paper	37	3.06
Book	23	1.90
Editorial	10	0.83
Note	2	0.17
Source Type	TP	%
Journal	1011	83.69
Book	146	12.09
Conference Proceeding	26	2.15
Book Series	24	1.99
Trade Journal	1	0.08
Language	TP	%
English	1172	97.02
Spanish	14	1.16
German	9	0.75
Portuguese	6	0.50
Turkish	4	0.33
Chinese	3	0.25
Slovenian	3	0.25
French	2	0.17
Dutch	1	0.08
Greek	1	0.08
Japanese	1	0.08
Korean	1	0.08
Russian	1	0.08

presents information on publications in the field of PL from 1992 to 2022. Most of them are Articles (78.73%), and Book Chapters also have a large share (10.84%).

After identifying the literature and sources again, the language was also considered, and as shown below in Table 3, English (n = 1172) accounts for the largest percentage of the 1208 documents, with 97.02% of the total number of publications. In addition, there are documents in Spanish, German, Portuguese, Turkish, Chinese, Slovenian, and French, while other languages account for a very small percentage and number of publications.

4.1.2. Annual Publication Trends

The section on annual publication trends from 1992 to 2022 includes important information on total publications, number of cited papers, and total citations (TC). According to this bibliometric data collection and analysis, as shown in

Table 4. Annual Publication Trends (TP = Total Publications; NCP = Number of Cited Papers; TC = Total Citations; h = h-index; g = g-index).

Year	TP	NCP	TC	h	g	Citable Year
1992	5	4	270	3	5	32
1993	4	4	60	3	4	31
1994	8	7	488	6	8	30
1995	9	8	263	5	9	29
1996	9	9	332	8	9	28
1997	8	8	182	5	8	27
1998	7	5	257	4	7	26
1999	18	15	282	7	16	25
2000	18	17	1461	8	18	24
2001	18	17	571	9	18	23
2002	18	17	366	10	18	22
2003	24	21	860	13	24	21
2004	26	24	1129	15	26	20
2005	30	25	1057	15	30	19
2006	35	32	1947	21	35	18
2007	38	36	3517	20	38	17
2008	42	39	2525	21	42	16
2009	47	44	1634	23	40	15
2010	42	40	1721	21	41	14
2011	42	42	1207	18	34	13
2012	53	45	999	18	30	12
2013	53	48	866	16	28	11
2014	52	46	1018	18	30	10
2015	50	43	940	16	29	9
2016	82	71	1075	20	29	8
2017	75	67	1193	19	32	7
2018	64	59	725	14	24	6
2019	93	70	537	12	19	5
2020	74	58	544	13	20	4
2021	75	60	241	7	10	3
2022	89	42	100	5	5	2
Grand Total	1208	1023	28,367	393	686	32

, there is an overall trend of growth in terms of total publications (TP), with explosive growth in 2016 (n = 82). Then, 2019 (n = 93) and 2022 (n = 89) have the highest number of publications; however, the numbers of publications in 2020 and 2021 significantly decreased with, respectively, 74 and 75 publications.

It can be observed in Figure 3 that after the period from 1999 to 2002, the studies on PL show a steady increase. Until the peak in 2019, the number of relevant studies increased relatively steadily from 2003 to 2018 but increased abruptly in 2016.

It is noteworthy that due to the COVID-19 epidemic, there was a certain lag in research in all fields globally, and for safety purposes and quarantine needs, researchers reduced exposure to and research on preschool-aged children, which in turn led to a decrease in the number of publications. The decline in the number of publications from 2020 to 2021 is reflected in this study. Based on the trends overall, the use of literacy in preschool will become a popular topic. Future researchers may look for potential research directions in Table 4 and Figure 3 of this study. After the annual publication trends are identified, the most highly cited documents are counted.

4.1.3. Most Cited Documents

The data for this bibliometric did not distinguish between country and language; therefore, the most cited papers on a global scale are shown in Table 5.

Citations, from an objective perspective, reflect the actual productive use of an article and, due to this, reduce the limitations of subjective evaluation [54]. Citation counts can be used as a reliable indicator of the quality of research publications and articles over time [55]. For the data in this study, the top 20 papers based on total citations have more impressive indicators. Most notably, the most cited paper, with 2006 citations, by Clancy Blair and Rachel Razza [56], examined children’s self-regulation in learning skills and demonstrated that this was related to measures of literacy in kindergarten [56]. The total citations (TC) and citations per year (C/Y) of this article are far ahead of those of other papers, which may explain the sudden increase in the TC in 2007 shown in Figure 3. Similar to this is the increase in TC for 2000 in Figure 3, which is attributed to the article by Christopher Lonigan, Stephen Burgess, and Jason Anthony [1] shown in Table 5, with a total citation count of 645. This article addresses the relationship between emerging literacy skills in preschool and later reading periods earlier than the first cited article and verifies the critical role of letter knowledge and phonological sensitivity for preschoolers [1]. It is inspiring to note that in these first 20 contributions, the focus is on the impact of the home literacy environment, literacy, and reading on children’s development [6,57,58,59]. There are also papers that discuss the role of teacher quality in the teaching process to improve language and literacy in preschool children, as well as studies on the relationship between literacy and language variables [3,5,60,61,62,63,64,65].

Table 5. Top 20 Highly Cited Documents (TC = Total Citations; C/Y = Citations per Year).

N	Document Title	TC	C/Y	Source
1	Relating effortful control, executive function, and false belief understanding to emerging math and literacy ability in kindergarten	2006	118.00	[56]
2	Development of emergent literacy and early reading skills in preschool children: evidence from a latent-variable longitudinal study.	645	26.87	[1]
3	Effects of the home learning environment and preschool center experience upon literacy and numeracy development in early primary school	415	25.93	[6]
4	Quality of language and literacy instruction in preschool classrooms serving at-risk pupils	392	24.50	[3]
5	Testing the home literacy model: Parent involvement in kindergarten is differentially related to grade 4 reading comprehension, fluency, spelling, and reading for pleasure	382	21.22	[57]
6	The role of home literacy environment in the development of language ability in preschool children from low-income families	364	12.13	[58]
7	The Comprehensive Language Approach to Early Literacy: The Interrelationships among Vocabulary, Phonological Sensitivity, and Print Knowledge among Preschool-Aged Children	356	16.95	[5]
8	Spoken word recognition and lexical representation in very young children	325	13.54	[66]
9	Preschool instruction and children’s emergent literacy growth	284	15.77	[67]
10	The role of home literacy practices in preschool children’s language and emergent literacy skills	266	14.00	[68]
11	Oral discourse in the preschool years and later literacy skills	247	12.35	[69]
12	Preschool Home Literacy Practices and Children’s Literacy Development: A Longitudinal Analysis	237	14.81	[70]
13	Young children learning Spanish make rapid use of grammatical gender in spoken word recognition	231	13.59	[60]
14	The effect of family literacy interventions on children’s acquisition of reading from kindergarten to grade 3: A meta-analytic review	228	14.25	[71]
15	Project EASE: The effect of a family literacy project on kindergarten students’ early literacy skills	201	8.38	[59]
16	Untangling the effects of shared book reading: Multiple factors and their associations with preschool literacy outcomes	199	12.44	[61]
17	Do Early Talkers Become Early Readers? Linguistic Precocity, Preschool Language, and Emergent Literacy	189	5.91	[62]
18	Affordances and limitations of electronic storybooks for young children’s emergent literacy	188	20.89	[63]
19	The impact of a clinic-based literacy intervention on language development in inner-city preschool children	185	8.04	[64]
20	Relations among preschool teachers’ self-efficacy, classroom quality, and children’s language and literacy gains	178	12.71	[65]

Table 5. Top 20 Highly Cited Documents (TC = Total Citations; C/Y = Citations per Year).

N	Document Title	TC	C/Y	Source
1	Relating effortful control, executive function, and false belief understanding to emerging math and literacy ability in kindergarten	2006	118.00	[56]
2	Development of emergent literacy and early reading skills in preschool children: evidence from a latent-variable longitudinal study.	645	26.87	[1]
3	Effects of the home learning environment and preschool center experience upon literacy and numeracy development in early primary school	415	25.93	[6]
4	Quality of language and literacy instruction in preschool classrooms serving at-risk pupils	392	24.50	[3]
5	Testing the home literacy model: Parent involvement in kindergarten is differentially related to grade 4 reading comprehension, fluency, spelling, and reading for pleasure	382	21.22	[57]
6	The role of home literacy environment in the development of language ability in preschool children from low-income families	364	12.13	[58]
7	The Comprehensive Language Approach to Early Literacy: The Interrelationships among Vocabulary, Phonological Sensitivity, and Print Knowledge among Preschool-Aged Children	356	16.95	[5]
8	Spoken word recognition and lexical representation in very young children	325	13.54	[66]
9	Preschool instruction and children’s emergent literacy growth	284	15.77	[67]
10	The role of home literacy practices in preschool children’s language and emergent literacy skills	266	14.00	[68]
11	Oral discourse in the preschool years and later literacy skills	247	12.35	[69]
12	Preschool Home Literacy Practices and Children’s Literacy Development: A Longitudinal Analysis	237	14.81	[70]
13	Young children learning Spanish make rapid use of grammatical gender in spoken word recognition	231	13.59	[60]
14	The effect of family literacy interventions on children’s acquisition of reading from kindergarten to grade 3: A meta-analytic review	228	14.25	[71]
15	Project EASE: The effect of a family literacy project on kindergarten students’ early literacy skills	201	8.38	[59]
16	Untangling the effects of shared book reading: Multiple factors and their associations with preschool literacy outcomes	199	12.44	[61]
17	Do Early Talkers Become Early Readers? Linguistic Precocity, Preschool Language, and Emergent Literacy	189	5.91	[62]
18	Affordances and limitations of electronic storybooks for young children’s emergent literacy	188	20.89	[63]
19	The impact of a clinic-based literacy intervention on language development in inner-city preschool children	185	8.04	[64]
20	Relations among preschool teachers’ self-efficacy, classroom quality, and children’s language and literacy gains	178	12.71	[65]

4.1.4. Most Productive Authors, Institutions, Countries, and Source Titles in PL

• Most Productive Authors

Among the 1208 documents, some authors are very prolific, publishing more papers and contributing to PL.

Table 6. Top 15 Most Productive Authors (TP = Total publications; NCP = Number of cited papers; TC = Total Citations; h = h-index; g = g-index; PYS = Publication Year Start).

N	Author’s Name	TP	NCP	TC	h	g	Citable Year	PYS
1	Justice, Laura M.	31	30	1592	20	1	20	2004
2	Piasta, Shayne B.	18	18	731	12	0	14	2010
3	Lonigan, Christopher J.	16	16	1574	14	0	25	1999
4	Marsh, Jackie	13	11	392	8	1	21	2003
5	Kaderavek, Joan N.	9	9	542	9	0	20	2004
6	Guo, Ying	9	9	382	7	0	14	2010
7	Verhoeven, Ludo	8	8	81	5	1	15	2009
8	Saracho, Olivia N.	8	8	102	5	0	24	2000
9	McGinity, Anita S.	8	7	357	6	1	14	2010
10	Skibbe, Lori E.	7	7	234	7	0	14	2010
11	Phillips, Beth M.	7	7	457	6	0	25	1999
12	Morrison, Frederick J.	7	7	821	7	0	26	1998
13	Greenwood, Charles R.	7	7	183	5	0	20	2004
14	Schachter, Rachel E.	6	6	142	4	1	8	2016
15	Oakley, Grace	6	4	28	2	2	6	2018

presents the top 15 highly productive authors, measured and rated on multiple dimensions such as total publications (TP), number of cited papers (NCP), total citations (TC), h-index, g-index, and publication year start. As shown in Table 6, Laura Justice is the leading author in PL with the most publications, contributing 31 papers from 2004 up to 2022. This is followed by Shayne Piasta with 18 publications, Christopher Lonigan with 16, and Jackie Marsh with 13. It is worth highlighting that, with regard to citation counts, the data sources are based on the number of citations per document in Scopus and thus generated, which therefore inevitably includes some self-citation. As researchers often explore related issues from different research perspectives and multiple aspects, this multi-faceted approach contributes to a comprehensive understanding of the complexity of PL and advances the field further.

2.

Most Productive Institutions

This bibliometric analysis also includes data cleaning and screening, ranked by TP, and presents the top ten institutions in terms of the authors’ affiliations or the name of the institution that signed the paper. Among them, as shown in

Table 7. Top 10 Most Productive institutions (TP = Total publications; TC = Total Citations; PYS = Publication Year Start).

N	Institution	TP	TC	PYS
1	The Ohio State University	84	2763	2010
2	Florida State University	54	3534	1999
3	University of Virginia	39	1877	2002
4	Griffith University	38	1616	2008
5	University of Toronto	33	378	2006
6	University of Sheffield	31	860	1998
7	Purdue University	30	1465	1999
8	University of Michigan	26	2578	1998
9	University of California	26	619	1993
10	Georgia State University	22	519	2002

, the most productive institution is the Ohio State University, which contributes a total of 84 publications and is the most productive in discussing and publishing articles related to PL. In addition, Florida State University, the University of Virginia, and Griffith University also produced good results, ranking second (n = 54), third (n = 39), and fourth (n = 38).

However, in terms of TC, Florida State University is better than Ohio State University, with the University of Michigan following closely behind. Looking at the PYS, the high-producing institutions started their research in the field of PL around 2000, a time frame in which they successively conducted their research. Looking at it today, all these institutions have gained a decade or two of research experience, laying the groundwork for further research in other structures.

3.

Most Productive Countries

The top 20 most productive countries are listed in

Table 8. Top 20 Most Productive Countries (TP = Total publications; % = Percentage).

N	Country	Continent	TP	%
1	United States	North America	621	51.41
2	Australia	Oceania	123	10.18
3	United Kingdom	Europe	100	8.28
4	Canada	North America	82	6.79
5	Germany	Europe	30	2.48
6	Netherlands	Europe	24	1.99
7	Norway	Europe	21	1.74
8	New Zealand	Oceania	20	1.66
9	Finland	Europe	19	1.57
10	Indonesia	Asia	19	1.57
11	Israel	Asia	17	1.41
12	Sweden	Europe	17	1.41
13	Hong Kong, China	Asia	16	1.32
14	China	Asia	15	1.24
15	Turkey	Europe	15	1.24
16	Spain	Europe	13	1.08
17	Italy	Europe	12	0.99
18	Portugal	Europe	12	0.99
19	Singapore	Asia	10	0.83
20	Chile	South America	9	0.75

. The highest number of published research papers on PL is from the United States (n = 621), accounting for 51.41% of the total, and it is certain that the United States has a leading position in this field. It is followed by Australia (n = 123), the United Kingdom (n = 100), and Canada (n = 82), which also have high numbers of publications. They are followed by Germany, the Netherlands, Norway, New Zealand, Finland, Indonesia, Israel, Sweden, Hong Kong (China), China, Turkey, and Spain, each contributing more than 1% of the total number of articles. In terms of the overall distribution, the high-producing countries for PL research are concentrated in North America, Europe, Oceania, and Asia.

4.

Most Productive Source Titles

This study considered 1208 publications in numerous journals. The results of the analysis for the source publications in this study are shown in

Table 9. Top 10 Most Productive Source Titles (TP = Total publications; TC = Total Citations; PYS = Publication Year Start).

N	Source Title	TP	TC	PYS	CiteScore2021	SJR2021	SNIP2021	Quartile
1	Early Childhood Education Journal	47	557	1995	2.9	0.637	1.696	Q2
2	Journal of Early Childhood Literacy	41	1100	2001	3.9	0.841	1.433	Q1
3	Early Child Development and Care	39	649	1993	2.3	0.452	0.98	Q2
4	Early Childhood Research Quarterly	36	2600	1993	6.2	1.653	2.053	Q1
5	Early Education and Development	22	635	1994	3.3	0.819	1.337	Q1
6	Reading and Writing	18	676	2001	4.3	1.219	1.846	Q1
7	Journal of Research in Childhood Education	17	358	1995	2.4	0.615	1.455	Q2
8	Topics in Early Childhood Special Education	15	474	1992	3.1	0.796	1.425	Q1
9	Journal of Early Childhood Teacher Education	14	66	2002	1.5	0.361	0.862	Q2
10	International Journal of Early Years Education	14	228	1999	2.5	0.488	1.512	Q2

. The most productive of these is Early Childhood Education Journal, which started publishing articles on PL in 1995 and published a total of 47 publications with a total of 557 citations by 2022. It is ranked as a Q2 journal in the Scopus database. It is followed by the Journal of Early Childhood Literacy (n = 41, Q1), Early Child Development and Care (n = 39, Q2), and Early Childhood Research Quarterly (n = 36, Q1). Notably, the top ten most productive journals according to CiteScore 2021 scores are now also high-quality journals in Q1 and Q2.

4.2. Top Keywords

Regarding the visual statistics of top keywords, the Word Cloud feature of Biblioshiny was used in this study [52].

Figure 4 is based on the authors’ keywords; the top 90 words or phrases most used in text retrieval were selected. Among them, the most popular word clouds include “literacy, emergent literacy, early literacy, early childhood, early childhood education, kindergarten, home literacy environment quality, language, reading, and literacy practices”. This can be seen to be consistent with the theme of this study, which supports the construction of the keyword network that follows.

4.3. Collaboration and Network Analysis

4.3.1. Co-Authorship in PL

The above sections present basic information on the bibliometrics of PL and the most productive components. Collaborative analysis is necessary to gain a deeper understanding of the literature on PL. This is because, with the increase in diversity and interaction between different fields, the analysis of specific researchers or topics can jointly contribute to the current body of knowledge [72]. It is worth noting that co-authorship has many aspects, the most influential being informal and relational, which are not directly related to the sharing of other resources [73]. Co-authorship, therefore, stands for research collaboration. It is an enabling mechanism for linking different scholars to generate research contributions and facilitates other researchers in understanding the co-authorship network, exploring potential gaps, and broadening and enriching the contributions to knowledge [74].

For the visual analysis of co-authorship networks for PL in this research bibliometric study, the author-based co-authorship map and the country-based co-authorship map were chosen.

• Co-Authorship by Authors

A co-authorship is defined as two or more authors co-authoring a published article; they are then considered to have a mutual collaborative relationship, and the authors will be connected in a collaborative network map [75]. The co-authorship graph is beneficial in helping researchers seek information about potential collaborations, while for publishers, it is advantageous for forming editorial teams [76].

Figure 5 presents an author-based co-authorship map that shows the names of authors who have published in the field of PL. Authors with a minimum productivity of three documents were selected in the VOSviewer technique, and a total of 154 out of 2736 authors reached the threshold, but only 39 authors were interlinked. Interestingly, the links between the bubbles indicate the co-authorship of the papers, while the size of the bubbles corresponds to the number of papers published by each author in the publication list, and the thickness of the connecting lines represents the closeness of the co-authorship. In short, the links between the bubbles show the co-authorship of the papers.

Currently, there is a trend toward sharing authorship among organizations in different fields, or among experts in different countries. Figure 5 illustrates that authors are divided into seven clusters, and those belonging to the same cluster have close collaboration in PL research. Among them, Justice L.M., Piasta, Shayne B., and Lonigan C.J. have a high number of papers in the red, blue, and yellow clusters, respectively. Importantly, when ranking the authors by the number of links, it is clear that Justice L.M. in the red central node, who works at The Ohio State University, Columbus, United States, has co-authored with 17 authors from different clusters in publications on this topic.

2.

Co-Authorship by Countries

Figure 6 analyzes the key collaborations in the field of PL for each country. It can be easily understood by overlaying the visualization figure that scholars from the United States led the collaboration, followed by the United Kingdom, Australia, and Canada.

In fact, regarding preschool education, Western countries have rich research experiences and academic achievements, which play a key role in laying the foundation for the construction of the knowledge system in this field. With the further expansion of the exchange, it can be seen that there are some rising stars in Asian countries that have also taken their place in the PL discourse during the period from approximately 2016 to 2018, such as China, Indonesia, Malaysia, and South Korea. Among these, China and South Korea are considered to be the closest Asian collaborators working with the United States.

4.3.2. Co-Occurrence Network of PL

Figure 7 shows a visual network of overlays based on author keywords, indicating the latest progress of PL research. The overlay color of each bubble corresponds to the average year of publication of all articles containing the corresponding keyword. The cool colors (such as purple) represent research activities with older average publication years, and the warm colors (such as yellow) show keywords with more recent average publication years. Specifically, the gradual transition from purple to blue, to green, and then to yellow in the lower right corner of Figure 7 reflects the changes made by co-occurring keywords as the year evolves. The sparsity of the curves in the figure represents the strength of the relationship between the keywords. No connecting line for keywords indicates that no association has been established between them. In addition, when authors use keywords that are more similar, as reflected in the bubbles in the figure, the distance between the bubbles can be observed; the closer the distance is, the stronger the relationship is. The size of the bubbles also represents how many times they are cited or not.

In this regard, it can be identified that the initial focus was on literacy and language studies, such as knowledge of vocabulary, pronunciation, listening and reading, spelling, and oral learning. The focus develops into the influence of teachers on students and gradually extends to the field of school-centered preschool education. It is clearly evident that at this stage, scholars in various countries have paid more attention to the improvement of children’s literacy learning skills and extended them to more specific and detailed directions, such as activities, shared reading, experiential learning, the home environment, and mathematics. Overall, the research with PL seems to have found a breakthrough for scholars to dig deeper.

The co-occurrence network analysis based on Title and Abstract fields took thirty years of data from 1992 to 2022 and set the minimum number of occurrences of a term at 13 in VOSviewer, with 409 thresholds out of 17,127 terms. The results are shown in three clusters, as shown in Figure 8. The authors integrated the colors based on the images, and the combination of each cluster represents a research direction. Specifically, there are three colors: red, green, and blue.

From the overall view of the visual structure map, there are closer connections between the different colored regions. The bubbles indicate the occurrence of specific terms such as child, literacy, and young child in the literature, and the lines indicate the co-occurrence relationship of these keywords in the literature.

Bubbles such as child, literacy, study, skill, and teacher are more prominent in Figure 8. Larger or darker bubbles usually indicate more important or frequently occurring keywords [77]; this allows researchers to understand that these terms have a higher level of interest in the literature.

Regarding the cluster and module aspects of the map, the red area presents the terms child, study/home environment, reading, parent, relationship, and literacy skills, which indicates the high internal connectivity of this bubble group. The green section presents the terms literacy, student, knowledge, early childhood, and research, which are modules that reveal the different themes presented in the research area and the correlations between them. Similarly, in the blue area, group, program, and impact are interspersed in the red and green areas, indicating the frequency of co-occurrence between keywords. These linking relationships can effectively reveal related topics or research hotspots in the research area.

4.3.3. Thematic Evolution of PL

Thematic evolution is an important aspect that affects the quality and results of the searches performed [78]. Figure 9 illustrates the process of topic evolution based on the authors’ keywords in a study related to PL. This visual representation allows one to clearly visualize the linear evolution of individual words or phrases and helps to understand the results obtained. From the figure, it is possible to see the evolution of the themes related to PL in the early period (1992–2022), in the middle period (2003–2012), and in the late period (2013–2022). Over a thirty-year period, the six themes in the early period evolved into nineteen themes in the middle period, and finally into nine themes. In Figure 9, “emergent literacy” and “young children” frequently appear together, suggesting that these two themes are closely associated in the study of preschool children’s literacy. In the early period, fewer papers focused on “family environment” and “reading skills”, but later on, “preschool education” and “literacy practices” gradually became the focus of research.

5. Discussion

This is the first bibliometric analysis of preschool literacy (PL) and is a convergence and expansion of research on literacy as well as preschool education. The aim of this study was to interpret and analyze the eligible data, extract key words, and construct connections so as to further explore the themes and possibilities for future research on PL and to point researchers in the right direction. In addition, this bibliometric analysis also explains the limitations of the study, with the intention of providing readers and practitioners in the field of PL with ideas to collectively identify research gaps and, in turn, contribute more to existing knowledge. Based on the results of the study, the next step is to respond to the research questions one by one.

5.1. What Are the Publishing Trends in Preschool Literacy (PL) Studies?

RQ1 is devoted to a bibliometric analysis of trends in literacy in preschool education. A total of 1208 relevant publications on PL were retrieved from the Scopus database, with an overall trend of an increase in the number of publications per year based on the year of publication. The number of publications was limited between 1992 and 2005 and has continued to increase since 2006. However, the period 2019–2021 shows a downward trend influenced by COVID-19. In 2022, the number of publications gradually picks up, a finding that can be explained as a growing emphasis on twenty-first-century skills (literacy skills) in the field of preschool education, skills that were frequently discussed in the 2000s and more recently. The study of annual publications and trends in publication type and language can provide relatively clear direction and guidance for future researchers. The analysis of these data clearly shows that PL is receiving much attention from researchers and is becoming increasingly popular. In particular, the publication of English-based articles represents the main type of contribution to the field. In addition, the number of studies in areas other than PL skills (e.g., technological literacy, physical literacy, financial literacy) has increased significantly in recent years [79,80,81]. Though the Scopus literature database provides rich literature information, including authors, citation data, and journal impact factors, it still cannot cover all academic literature, and it may have some under-coverage of fields, regions, or specific types of literature. For future researchers, it is meaningful to screen different literature databases as well.

5.2. Which Are the Most Productive and Influential Authors, Affiliations, and Countries in the Study of Preschool Literacy (PL)?

The results of the RQ2 study show the top 15 most productive and influential authors, the top 10 institutions, the top 20 countries, and the top 10 journals, as well as the top 20 most cited papers. The findings indicate that the United States is dominant in the field of PL and has a large number of scholars published in the top journals. This finding is attributed to the United States federal government’s focus on improving literacy since 2001, with the No Child Left Behind (NCLB) series of regulations including two literacy programs, primarily for children in preschool through third grade. In addition, many countries in North America, Oceania, and Europe have contributed many high-quality papers, including Australia, the United Kingdom, Canada, Germany, the Netherlands, and Norway. Asian countries and regions, as latecomers, also appear in PL-related studies; examples include Hong Kong (China), China, and Indonesia.

Not surprisingly, Western education leads the way in research on language literacy initiation and has profoundly influenced countries worldwide, as can be understood from the list of institutions, with United States institutions (universities) having a high output in this area, contributing to the development of PL. For example, Clancy Blair and Rachel Razza [56] in the United States published “Relating effortful control, executive function, and false belief understanding to emerging math and literacy ability in kindergarten” in 2007, and this publication has over 2000 total citations. In addition, Early Childhood Education Journal, Journal of Early Childhood Literacy, Early Child Development and Care, and Early Childhood Research Quarterly are the top four journals and have contributed the most to the development of PL. Thus, this finding indicates that the above journals have gained an international reputation in the field of literacy skills. Practitioners in the field of PL can contribute to knowledge by conducting further research and analysis with the help of the top 10 journals provided in this study to explore potential research topics, which in turn can fill more research gaps in PL.

It is undeniable that self-citation exists in the highly productive author section. However, in this study, the researchers chose to take self-citation into consideration to provide a more comprehensive perspective to assess the productivity of the authors. In the field of PL research, relevant issues are often explored from different research perspectives and from multiple aspects. This multi-perspective approach to research helps to comprehensively understand and explain the complexity of PL and to promote further development of the field. Therefore, self-citation is considered in this study as a further depth and development of previous research and can provide a continuum of perspectives to help researchers make connections in different directions and continue to contribute to the field of PL. However, self-citation may at some point cause artificial inflation of citation counts and impact metrics to some extent, and therefore future researchers need to carefully consider whether to include self-citation in relevant studies, depending on the field of study.

In addition, an analysis based on journals and papers demonstrates that PL, as a necessary skill for students before entering elementary school, frequently goes beyond the role that particular factors play in children’s development. Long-term active and emerging research topics emphasize integrated studies that go beyond the limitations of a single element, such as the assessment of literacy [8]. In addition, future research should include multi-element and multi-domain integrative research, which means focusing on the effects of more pre-service teacher training, home environment, social status, and technology applications on the emergent literacy of preschool children [82,83]. In general, long-term, active, and emerging research topics are critical to current research. Thematic diversity in research is the future trend and direction of PL.

5.3. What Are the Knowledge Structures Presented in Preschool Literacy (PL) Studies in Terms of Collaboration and Co-Occurrence Networks?

RQ3 explores PL research in terms of collaborative and co-occurrence networks, which present knowledge structures designed to reveal the knowledge ecology of the PL field, identify key researchers, discover research themes and hotspots, and promote disciplinary communication and collaboration. This analysis can provide insights and understanding that can help advance PL. This study reveals that PL has been discussed in the context of kindergarten instruction, home education, and teaching methods through author keywords, co-occurrence analysis, and co-authorship analysis. Among the various studies, it can be understood that many researchers have a dialectical analysis of the use of methods by preschool teachers in teaching, as the traditional teaching methods are not sufficient to support the growing literacy needs of children [84]. Therefore, pre-service and post-service training should be increased for preschool teachers in future preschool education [84]. Emphasis should also be placed on joint teacher–child participation, where children and teachers engage in socially conscious interactive practices together, to help children learn and integrate into social relationships and be part of the community to which they belong [85]. In parallel, kindergartens have an obligation to channel the knowledge of parents, as well as quality participation to support the family role, thus promoting the full development of the child [86]. However, limitations exist, and although research and outputs on PL continue to grow, specific research directions in PL are not effectively explored, and the lack of links between fragmented research directions can also be seen through the visualization. In addition, even though major research institutions have begun to explore the sustainability of PL, it is still not widely used and practiced in kindergartens. In this regard, there is still a need for further validation and research on the effectiveness of preschool theories and literacy knowledge system construction practices on preschool children. In terms of citation relationships and knowledge dissemination, some early studies were frequently cited while others were less commonly cited, and there may be uneven or limited knowledge flow [3,5,66,67,69].

It is also worth discussing that the intensity of collaboration between countries is still insufficient based on co-authorship analysis and co-occurrence network analysis. Therefore, it is recommended to actively expand the collaboration of international researchers or joint research between institutions in future studies.

5.4. What Are the Most Prevalent Themes of Preschool Literacy (PL) among Scholars?

By analyzing the abstracts and titles in the bibliometric data (see Figure 8) and the thematic evolution (see Figure 9), the contribution network was visualized. The first deals with the core content and key elements of PL, such as “reading”, “phonological awareness”, and “home environment”. In the practice of PL research, attention to these concepts and core elements can provide a solid foundation for children’s literacy development. For example, Kulju and Mäkinen [87] observed that a variety of phonological strategies (syllable division of words, phonological processing, and letter names) adopted in literacy play can support preschoolers’ literacy development. Meanwhile, Napoli et al. [88] examined the effects of child and family characteristics related to the home literacy environment on children’s literacy in the same sample. In addition, Giacovazzi et al. [89] also proposed adding environmentally friendly print materials to stimulate emergent literacy in young children, with results suggesting a short-term, teacher-based intervention that used environmental printing to improve preschoolers’ emergent literacy skills. Nonetheless, the use of small or population-specific samples or short-term intervention programs may not adequately represent the diversity and complexity of the broader preschool population [90,91,92]. Therefore, for future researchers, there should be a balance between enhancing research, expanding sample size, and tracking long-term effects. This will help develop a deeper understanding of the core content and key elements of PL and improve the quality of PL research.

In terms of changes in research methods and design and strategies for literacy learning, researchers can understand the application of different research methods in PL research and the emergence of emerging methods and designs, which helps researchers understand the development and improvement of PL research methods. In addition, a number of researchers have conducted studies from teachers’ perspectives, such as interviews with teachers, questionnaires, and action research [25,84]. In addition, after having literacy skills, good learning styles and strategies can promote the sustainable development of the skills. An example is the use of digital resources for literacy. This provides sustainable literacy learning strategies for preschools and teachers. This leads to better advancement of PL and promotes the physical and mental health of preschool children [93]. There are many aspects of preschool education that need to be considered. For literacy, the most immediate question is as follows: how is “literacy” received and understood, and what methods are used to master the content? And how can preschoolers better absorb the knowledge? A network of co-occurrence relationships from the bibliometric analysis provides direction. It is important to note that early childhood teachers and parents should listen to children, give feedback, and provide support to facilitate the transition to elementary school [38]. The context of teaching and learning is always changing, such as with the global epidemic of the previous two years, which led to unexpected changes in the way preschoolers learn to read and write. For now, it is difficult to speculate as a researcher on the good and bad of this. Rather, researchers should build on it and attempt more research to validate or explore the opportunities for literacy and to encourage a broad and inclusive approach to literacy instruction that moves beyond multimodality and embraces the diversity of readers, texts, media, activities, settings, and contexts for the 21st century [94]. However, for preschoolers, the availability of more methods for learning does not necessarily lead to better outcomes; it is necessary to stand up for the children and explore what really works for them, which in turn promotes their literacy skills.

It is worth noting that although literacy is widely discussed in the field of education, the sustainability of PL still has more potential to be explored. Literacy intervention projects, or programs, constitute the starting point for planning a multimodal approach to literacy development for future educators [95,96,97]. In this study, it is probably reflected in words such as group, program, project, model, and activity. Furthermore, through a careful analysis of the literature, it can be ascertained that more and more researchers are committing to specific intervention studies and collecting data in a more targeted manner after developing a careful strategy. For example, Ihmeideh and Al-Maadadi [97] designed a family literacy program that tested five aspects of “concepts of print, phonological awareness, letter knowledge, vocabulary, and emergent writing”. The results showed that the children in the experimental group of the program scored significantly higher than the control group in the early literacy test. Meanwhile, Bulotsky Shearer et al. [98] concluded that the ecological model supports challenging behaviors in preschool learning environments and that children show high levels of language and literacy, but that sustained positive output requires support from policy and teacher practice. However, intervention programs for PL have not been adequately studied. Interventions not only need to be tracked for long-term effects, but future trends favor diversified intervention strategies such as technological interventions as well as interdisciplinary collaborations [26].

6. Conclusions

Based on 1208 publications in the Scopus database, this study aimed to understand the concerns, methodological changes, collaborative networks, guidance for policy development, and practical applications of PL research for the further development and application of PL research. The number of publications has steadily increased over a thirty-year period beginning in 1992, and based on an analysis of the results, it can be predicted that future growth trends will remain optimistic. The results of this study showed that the United States, as a pioneer in the field of PL, has also progressively collaborated and conducted research with other countries, and many publications as well as authors likewise have an international collaborative posture. These existing co-occurrence networks can provide more opportunities for researchers and practitioners from other countries and regions to collaborate. In addition, the study found that Early Childhood Education Journal, Journal of Early Childhood Literacy, Early Child Development and Care, and Early Childhood Research Quarterly are the most active journals with a strong academic discourse in the field of PL and are strong references for future research by future researchers.

In fact, this paper contributes to the theory by identifying important areas for future research. At the same time, the analysis based on this bibliometric study also reveals that with the progress of the times and the progressive exploration of teaching and learning approaches, new areas of research such as emerging literacy skills, family-based literacy models, and literacy intervention models have emerged. It can be stated that this study has enhanced the understanding of PL aspects.

However, there are still limitations to this study that need to be addressed. As far as databases are concerned, the sample size of Scopus is certainly large, but it cannot guarantee coverage of all kinds of database articles, so this study also recommends that more researchers search for information on different literature data to enrich the knowledge in the field of PL. In addition, the results of the study also suggest that there is space for exploration in PL research. In this regard, it is important to consider not only the conceptual changes but also, more importantly, the literacy of preschool children over time, as well as the influence of cultural and social contexts on preschool children’s literacy. Therefore, in future research in this area, researchers should focus on the lasting effects of interventions on children’s literacy development in the long term. This study also encourages future researchers to be able to continuously expand collaborative research and break away from the concentration on a few core research teams. In summary, this bibliometric study is a statement of the importance of understanding trends and patterns in research on PL. Potential researchers are called upon and expected to be interested in exploring and acting more in this area to fill the research gaps and thus contribute to the integrity and systematic construction of the existing body of knowledge.