Understanding EFL Learners' Code-Switching and Teachers' Pedagogical Approaches in LLM-Supported Speaking Practice

TL;DR

This study explores how EFL learners' code-switching is supported by LLM-based tutors and how teachers adapt pedagogical strategies to enhance bilingual speaking practice, highlighting design implications for future LLM tutoring systems.

Contribution

It provides empirical insights into integrating code-switching support in LLM tutors and examines teachers' pedagogical responses to improve bilingual language learning.

Findings

Learners use CSW to express cultural and emotional nuances.

Teachers employ selective interventions and dynamic scaffolding.

Design implications for bilingual LLM tutors are proposed.

Abstract

For English as a Foreign Language (EFL) learners, code-switching (CSW), or alternating between their native language and the target language (English), can lower anxiety and ease communication barriers. Large language models (LLMs), with their multilingual abilities, offer new opportunities to support CSW in speaking practice. Yet, the pedagogical design of LLM-based tutors remains underexplored. To this end, we conducted a six-week study of LLM-mediated speaking practice with 20 Korean EFL learners, alongside a qualitative study with nine English teachers who designed and refined responses to learner CSW. Findings show that learners used CSW not only to bridge lexical gaps but also to express cultural and emotional nuance, prompting teachers to employ selective interventions and dynamic scaffolding strategies. We conclude with design implications for bilingual LLM-powered tutors that leverage teachers' expertise to transform CSW into meaningful learning opportunities.