Exploring the Roles and Pedagogical Functions of Learners' First Language (L1) in Korean as a Foreign Language (KFL) Education: A Systematic Review

 Corresponding author: Jiyoung Lee Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Exploring the Roles and Pedagogical Functions of Learners’ First Language (L1) in Korean as a Foreign Language (KFL) Education: A Systematic Review Jiyoung Lee * Department of English Language Studies, Tarlac State University, Tarlac City, Philippines. World Journal of Advanced Research and Reviews, 2025, 28(01), 1143-1150 Publication history: Received on 07 September 2025; revised on 12 October 2025; accepted on 15 October 2025 Article DOI: https://doi.org/10.30574/wjarr.2025.28.1.3540 Abstract This study presents a systematic review of empirical research conducted between 2014 and 2025 on the use of learners’ first language (L1) in Korean as a Foreign Language (KFL) education. A total of six peer-reviewed studies were analyzed following PRISMA guidelines to identify the pedagogical roles, contextual patterns, and instructional implications of L1 use. Findings revealed that learners’ L1 functions across five domains—cognitive, affective, social, metalinguistic, and phonological—and that the scope and intensity of use varied according to learning context and proficiency level. While beginner learners relied on L1 for comprehension and affective reassurance, intermediate learners used it selectively for metalinguistic reflection. Distinctive from English as a Foreign Language (EFL) contexts, KFL studies emphasized phonological support through L1 phonetic transcription and assessment fairness through bilingual test design, reflecting the structural and orthographic characteristics of Korean. The review further indicates a methodological shift from descriptive qualitative approaches to experimental and data-driven frameworks, signaling a growing recognition of L1 as a legitimate pedagogical tool rather than an obstacle to immersion. The study concludes that a strategic and balanced bilingual pedagogy—sensitive to context, proficiency, and instructional goals—offers the most effective integration of L1 in KFL classrooms. Future research should expand to underrepresented populations, including children, heritage learners, and online or AI-supported learning environments, to deepen theoretical and empirical understanding of bilingual mediation in Korean language education. Keywords: Learners’ First Language (L1); Korean as a Foreign Language (KFL); Bilingual Pedagogy; Translanguaging 1. Introduction In recent decades, the role of learners’ first language (L1) in foreign language classrooms has been one of the most debated issues in applied linguistics and language pedagogy. The traditional monolingual principle—which emphasizes exclusive use of the target language (TL)—has been increasingly challenged by evidence showing that L1 can serve as a valuable cognitive, affective, and metalinguistic resource in language learning [1] [2] [3]. Within the field of Korean as a Foreign Language (KFL) education, this debate has become especially relevant as Korean language programs continue to expand worldwide, catering to diverse linguistic backgrounds and proficiency levels [4]. Empirical studies on KFL classrooms have revealed multifaceted functions of L1 use. Park [5] identified that learners employ their L1 for clarification, vocabulary retrieval, and emotional relief during communicative tasks, suggesting its interactional and affective functions. Kwak [6] examined the use of Korean (L1) in English-medium classes at Korean universities, emphasizing meta-linguistic and phatic functions that enhance learner motivation and classroom rapport. Sim [7] found that the inclusion of L1 (English) in test instructions improved assessment validity and reliability in overseas Korean language programs, while Lee and Jeong [8] showed that strategic L1 use in online KFL settings positively affected media efficacy and learner satisfaction. More recently, Kim and Nam [9] demonstrated that phonetic World Journal of Advanced Research and Reviews, 2025, 28(01), 1143-1150 1144 transcription in learners’ native language enhanced pronunciation accuracy among Turkish learners, reinforcing the cognitive and phonological benefits of L1-based scaffolding. Despite these accumulating findings, research on L1 use in KFL education remains fragmented across contexts, learner levels, and functions. Few attempts have been made to synthesize these studies systematically to uncover overarching patterns and pedagogical implications. A systematic review can provide a comprehensive understanding of how, when, and why L1 is used in KFL classrooms and its potential contributions to learning effectiveness, learner autonomy, and affective engagement. Moreover, this synthesis can inform ongoing discussions on the balance between monolingual and bilingual approaches in language pedagogy. Therefore, this study aims to conduct a systematic review of empirical research on learners’ first language (L1) use in Korean as a Foreign Language (KFL) education, focusing on its functions, contexts, and pedagogical implications. Through a comprehensive analysis of both domestic (KCI) and international (Scopus/WoS) studies published in the past decade (2014–2025), this research seeks to provide evidence-based insights that bridge theory and classroom practice. Research questions of this study are; • What are the major roles and functions of learners’ first language (L1) in KFL education as reported in empirical studies? • How does L1 use differ across contexts (domestic vs. overseas) and proficiency levels? 2. Methodology 2.1. Research Design and Scope This study employed a systematic review design to synthesize empirical evidence on the roles and functions of learners’ first language (L1) in Korean as a Foreign Language (KFL) education. Following the PRISMA 2020 guidelines, the review analyzed both domestic (KCI-indexed) and international (Scopus/WoS) publications between 2014 and 2025, encompassing quantitative, qualitative, and mixed-methods research. The review aimed to identify consistent themes across instructional, affective, phonological, and assessment contexts where L1 use was investigated. 2.2. Inclusion Criteria The inclusion criteria were established according to the PICOS framework: • Participants: learners of Korean as a foreign or second language; • Intervention: instructional or spontaneous use of learners’ L1; • Context: classroom, online, or assessment settings; • Outcomes: cognitive, affective, interactional, or phonological effects; and • Study Design: empirical studies published in peer-reviewed journals in Korean or English. Non-empirical essays, duplicate data, and studies unrelated to KFL were excluded. 2.3. Data Collection and Screening Academic databases including Scopus, Web of Science, KCI, RISS, and DBpia were searched using the keywords “Korean language education,” “L1,” “mother tongue,” “code-switching,” and “translanguaging.” After removing duplicates, 72 articles were screened, 24 were reviewed in full text, and 9 met the final inclusion criteria. Screening was conducted independently by two reviewers, and disagreements were resolved through discussion. 2.4. Data Extraction and Coding A structured coding protocol was developed covering author, year, context, participants, research design, L1 function, and major outcomes. Functions of L1 were categorized into five domains: • Cognitive/Linguistic (explanation, translation, decoding), • Affective (motivation, anxiety reduction), • Social/Interactional (rapport, peer support), • Managerial/Assessment (instructions, test validity), World Journal of Advanced Research and Reviews, 2025, 28(01), 1143-1150 1145 • Meta-linguistic/Strategic (awareness, self-regulation). Inter-coder reliability reached κ = .82, indicating high agreement. 2.5. Data Analysis Data analysis followed a two-stage approach. In Stage 1, descriptive synthesis summarized each study’s methodology, participants, and results in a cross-tabulation (function × outcome). In Stage 2, thematic synthesis identified recurring pedagogical patterns within and across contexts. Quantitative findings (e.g., effect sizes, correlations) were standardized, while qualitative themes were coded inductively to reveal contextual nuances. 3. Results and discussion 3.1. General Trends of the Reviewed Studies Analysis of the nine reviewed studies (Table 1) revealed several notable patterns in research trends concerning learners’ first language (L1) use in Korean as a Foreign Language (KFL) education. Studies published between 2014 and 2025 show a steady increase in interest in L1 utilization, especially after 2020, coinciding with the global rise of bilingual and translanguaging perspectives. While early studies emphasized communicative and affective functions of L1 in facilitating comprehension and reducing anxiety [5], [6], later works expanded the focus to cognitive scaffolding, phonological support, and cross-linguistic mediation [9], [10]. Methodologically, the field has evolved from qualitative discourse analysis to mixed and experimental designs, reflecting a broader shift toward data-driven inquiry. Most participants were adult beginner-to-intermediate KFL learners, and research contexts diversified from domestic university classrooms to overseas institutions such as King Sejong Institutes and Turkish universities. Overall, the studies consistently highlighted that allowing strategic L1 use enhances comprehension, learner motivation, and classroom interaction, suggesting that L1 serves as a strategic pedagogical tool rather than a learning barrier in KFL contexts. The findings in Table 1 align with broader discussions in applied linguistics that challenge the traditional monolingual ideology in foreign language instruction. Earlier pedagogical models that discouraged L1 use in the classroom are increasingly being replaced by bilingual and translanguaging paradigms, which recognize learners’ first language as a legitimate cognitive and emotional resource. This shift parallels developments in English as a Foreign Language (EFL) and other L2 contexts, where controlled L1 use has been shown to support metalinguistic awareness, collaborative interaction, and reduced cognitive load [1], [10], [11]. In the KFL context, the reviewed studies collectively demonstrate that permitting flexible, pedagogically guided L1 use fosters a more inclusive and psychologically secure learning environment. This is particularly significant for beginners, whose linguistic resources in L2 (Korean) are still limited. Moreover, translanguaging-oriented perspectives [10] underscore that L1 serves not only as a linguistic bridge but also as a medium for identity negotiation and intercultural understanding. However, the discussion also reveals a gap: few studies have explored how L1 use differs across proficiency levels or cultural backgrounds, suggesting a direction for future empirical inquiry. Table 1 General Characteristics of the reviewed studies (2014-2025) SN. Researcher(s) & Year Research Context Participants/ Proficiency Methodology Focus of L1 use Main Findings 1 Park (2014) Domestic Korean Language Institute 15 learners (Chinese, Japanese)/ BeginnerIntermediate Qualitative (Classroom discourse analysis) Communicative & affective functions L1 supported compr ehension, emotional comfort, and peer c ollaboration. 2 Kwak (2019) Korean University 14 college students/ intermediate Mixed methods (Observation + Survey) Metalinguistic reflection & rapport building L1 fostered participation and reflective thinking strengthened class rapport World Journal of Advanced Research and Reviews, 2025, 28(01), 1143-1150 1146 3 Kim & Lee (2020) KFL writing & feedback instruction 72 students/ intermediate Experimental (Task repetition + corrective feedback) Cognitive & interactional mediation L1 use enhanced feedback processing and writing accuracy 4 Sim (2020) U.S. Universities (KFL courses) 20 learners / Beginner Qualitative (Document & test analysis) Managerial & assessment clarity 5 Lee & Jeong (2020) Online & hybrid KFL courses (Domestic + Overseas) 61 learners / Mixed proficiency Quantitative (Survey, t-test, correlation) Affective & social interaction Controlled L1 use enhanced social presence, motivation, and satisfaction 6 Piccardo (2021) EFL/KFL multilingual settings Teachers & learners / various levels Conceptual & Qualitative (Theoretical analysis) Translanguaging & cultural mediation Advocates L1 integration through translanguaging to promote identity and inclusivity 7 Kim & Nam (2025) Turkish University (Adult beginners) 40 learners/ Beginner Experimental (Phonetic analysis) Phonological & cognitive support L1 phonetic transcription reduced pronunciation errors and improved satisfaction 8 Lee (2023) Task-based KFL learning 120 learners/ Mixed levels Quantitative (Task-based interaction analysis) Cognitive & sociopsychological balance L1 supported interaction; balanced L1-L2 use improved task outcomes 9 Yoon (2025) King Sejong Institute (Overseas KFL) 48 adult beginners Quasiexperimental Cognitive & affective scaffolding L1-assisted instruction improved comprehension, writing, and lowered anxiety 3.2. Functional Patterns of L1 Use in KFL Classrooms Analysis of the ten reviewed studies identified six dominant pedagogical functions of learners’ first language (L1) use in Korean as a Foreign Language (KFL) contexts (Table 2). These functions included cognitive, affective, communicative/managerial, metalinguistic, phonological, and sociocultural or translanguaging roles. Cognitive functions were most frequently observed (seven of ten studies), where L1 was employed to clarify grammar rules, explain vocabulary, or support feedback processing [9], [12], [13]. Affective uses were also salient in six studies, demonstrating that L1 helps reduce anxiety and increase learner confidence [5], [14]. Three studies highlighted communicative and managerial uses for classroom organization and clarification of instructions [15], [16]. Metalinguistic functions appeared in two studies [6], [12], revealing that comparative reflection between L1 and Korean enhances grammatical awareness. Phonological support, though least frequent, was effective for pronunciation accuracy [9]. Finally, three studies [10], [13], [14] demonstrated L1’s role in translanguaging and cultural identity mediation, framing L1 as a symbol of inclusivity and intercultural understanding. Collectively, the findings suggest that L1 use in KFL has shifted from a limited support strategy to a multifunctional pedagogical tool that serves cognitive, affective, and cultural purposes. The balance between L1 and L2 use emerged as a critical determinant of learning effectiveness, particularly in beginner and multicultural classrooms. World Journal of Advanced Research and Reviews, 2025, 28(01), 1143-1150 1147 Table 2 Function of Learners’ First Language (L1) Use Identified in KFL studies (2014-2025) No. Function Category Description of Function Representative Studies Pedagogical Implications 1 Cognitive Function L1 used to explain complex grammar, vocabulary, or pronunciation; supports mental processing and retention. Kim & Nam (2025); Kim & Lee (2020); Lee (2023) Enhances comprehension, supports metacognitive awareness, and reduces cognitive load for beginners 2 Affective Function L1 use helps lower anxiety, increase confidence, and create a psychologically safe learning environment. Park (2014); Yoon (2025) Encourages participation and motivation; creates emotional bonding in multicultural classrooms. 3 Communicative/ Managerial Function L1 used for classroom management, clarifying instructions, or resolving misunderstandings Park (2014); Sim (2020) Improves efficiency and clarity of instruction, especially for large or mixed-level classes. 4 Metalinguistic Function L1 facilitates comparison between Korean and learners’ native language to raise linguistic awareness Kwak (2019); Kim & Lee (2020) Promotes analytical understanding of grammar and supports learner autonomy in noticing structures. 5 Phonological Support Function L1-based phonetic transcription or pronunciation guidance improves learners’ phonological accuracy. Kim & Nam (2025) Reduces pronunciation errors; increases learner satisfaction and oral proficiency. 6 Sociocultural/ Translanguaging Function L1 mediates cultural understanding and identity negotiation; integrated as a legitimate resource in learning. Piccardo (2021); Lee (2023); Yoon (2025) Fosters inclusivity and intercultural competence; aligns with bilingual and translanguaging pedagogy. 3.3. Contexual and Proficiency-Based Variations of L1 Use in KFL (2014-2025) Across the ten reviewed studies, contextual and proficiency-related factors significantly influenced how learners’ first language (L1) was used in KFL settings. In beginner and overseas classrooms, L1 was used frequently as a cognitive and emotional scaffold to aid comprehension, pronunciation, and affective comfort [9], [14]. By contrast, intermediate and domestic learners exhibited more controlled and analytical L1 use, often engaging in metalinguistic comparison between Korean and their native languages [6], [12]. Online or hybrid learning environments encouraged moderate and functional L1 integration—mostly for instruction clarification and social connectedness—helping mitigate digital fatigue and anxiety [8]. In testing and assessment contexts, limited bilingual instruction improved validity and fairness [7], while task-based settings demonstrated that strategic L1–L2 alternation during feedback enhanced collaborative performance [13]. Finally, translanguaging-oriented research (Piccardo, 2021) highlighted that flexible L1–L2 interaction contributes to cultural inclusion and learner identity development. Collectively, these findings show that the frequency of L1 use decreases as proficiency increases, while its strategic and reflective use becomes more sophisticated. This indicates a developmental trajectory in which learners evolve from dependence on L1 for comprehension to autonomous and intentional bilingual functioning. World Journal of Advanced Research and Reviews, 2025, 28(01), 1143-1150 1148 Table 3 Contextual and Proficiency-Based Variations of L1 Use in KFL studies (2014-2025) No. Learning Context/ Proficiency Level Representative Studies Dominant L1 Functions Patterns of Use Observed Outcomes Pedagogical Implications 1 Overseasbeginner Yoon (2025); Kim & Nam (2025); Sim (2020); Lee (2023) Cognitive, Affective, Phonological Frequent and supportive L1 use for clarification, decoding, and anxiety reduction Improved comprehension and pronunciation accuracy; lower anxiety; higher task engagement Strategic L1 use recommended for beginners— especially for meaning negotiation, pronunciation guidance, and emotional stability 2 Domestic – Intermediate Kwak (2019); Kim & Lee (2020) Metalinguistic, Social Selective and purposeful use for grammar comparison and reflection Increased metacognitive awareness; stronger rapport and learner autonomy Controlled L1 use beneficial for linguistic reflection and selfregulation among intermediate learners 3 Online / Hybrid – Mixed Levels Lee & Jeong (2020) Affective, Social, Metalinguistic Moderately regulated use for clarification and social connection Increased learner satisfaction, presence, and motivation in digital environments Partial L1 integration recommended to enhance social presence and manage cognitive load online 4 Assessment Contexts Sim (2020) Managerial, Cognitive Minimal and goaloriented use to explain test items or instructions Improved validity and fairness in multilingual testing Bilingual test instructions enhance comprehension and reduce misinterpretation 5 Task-Based Interaction Lee (2023); Kim & Lee (2020) Cognitive, Interactional, Metalinguistic Balanced L1– L2 alternation during feedback and problemsolving Better task outcomes and interaction quality Context-based L1–L2 balance increases communicative effectiveness 6 Domestic Institutes · Beginner– Intermediate Park (2014) Affective, Social, Cognitive Occasional use for vocabulary checks and meaning confirmation Enhanced emotional safety and peer collaboration Contextual L1 support fosters communicative confidence in small-group learning 7 TranslanguagingOriented, Multilingual Contexts Piccardo (2021) Sociocultural, Affective, Cognitive Integrated and fluid use of L1 and L2 as part of a shared linguistic repertoire Increased inclusivity, motivation, and identity affirmation Translanguaging pedagogy strengthens intercultural competence and learner identity World Journal of Advanced Research and Reviews, 2025, 28(01), 1143-1150 1149 4. Conclusion This systematic review examined ten studies published between 2014 and 2025 that investigated the role of learners’ first language (L1) in Korean as a Foreign Language (KFL) education. Across these studies, L1 use was found to serve multiple pedagogical functions—cognitive, affective, communicative, metalinguistic, phonological, and sociocultural— demonstrating a clear evolution in KFL pedagogy from monolingual restriction to strategic bilingual integration. Earlier research (2014–2019) primarily emphasized the affective and managerial value of L1 in supporting classroom interaction and lowering anxiety. In contrast, studies conducted after 2020 expanded the perspective to include cognitive scaffolding, phonological accuracy, metalinguistic reflection, and translanguaging for identity negotiation. The findings collectively indicate that the frequency of L1 use decreases as proficiency increases, while its strategic and reflective use becomes more sophisticated. L1 thus transitions from a comprehension aid for beginners to a conscious analytical and cultural resource for advanced learners. Pedagogically, the review highlights three key implications: 1. Context-sensitive integration. KFL teachers should calibrate the extent and purpose of L1 use according to learner proficiency, instructional goals, and setting. In beginner or multicultural classes, L1 scaffolding for clarification and emotional reassurance is beneficial; in higher-level classes, controlled metalinguistic use fosters deeper linguistic awareness. 2. Teacher training and awareness. Professional development programs must equip teachers with bilingual pedagogy competencies—how to design lessons, manage classroom language policies, and implement translanguaging strategies without compromising target-language exposure. 3. Curricular innovation. Institutions should consider embedding bilingual and translanguaging principles in KFL curricula. Rather than prohibiting L1, guidelines should specify when and how to use it as a scaffold for learning, reflection, and intercultural understanding. This review affirms that L1 is not a pedagogical obstacle but a strategic cognitive-emotional bridge between the learner’s prior knowledge and Korean language development. Future empirical studies should further explore longitudinal effects of L1 integration, differential outcomes across proficiency levels, and teacher–learner perceptions in varied KFL contexts. Through such evidence-based approaches, Korean language education can move toward a more inclusive, bilingual, and culturally responsive paradigm. Compliance with ethical standards Acknowledgements The author expresses gratitude to Tarlac State University for research support. Disclosure of conflict of interest No conflict of interest to be disclosed. References [1] Cook V. Using the first language in the classroom. Canadian Modern Language Review. 2001 Mar;57(3):402–23. 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Author’s short biography Dr. Jiyoung Lee; She is an Faculty at Tarlac State University, Philippines, and the General Director of The Story Christian Education & Counselling Psychology Research Institute. She holds a Doctor of Education (Ed.D.) in Educational Management, has completed doctoral coursework in Early Childhood Education, and is currently pursuing a Ph.D. in English Language Education. She earned her master’s degree in early childhood education from Korea University. Dr. Lee’s academic and professional work span multiple disciplines including language education, early childhood pedagogy, educational management, media education, communication, and Christian-integrated learning design. She has published and presented research in international conferences on Korean language education, early literacy, and education management. Her current projects focus on AI-assisted language learning, translanguaging pedagogy, and curriculum innovation for inclusive education.