highlight that bilingual learners strategically switch and mix languages to enhance

comprehension and interaction in classroom settings (Garcia & Wei, 2021; Cenoz & Gorter,

2022). In Indonesia’s multilingual setting, such alternation becomes a natural and frequent

phenomenon, especially in educational environments where English is taught as a foreign

language.

maintain interaction (Almoaily, 2021; Setiawan & Qodriani, 2021). Code mixing, on the

other hand, often involves the insertion of linguistic elements from one language into

another—a process conceptualized by Muysken (2000) as insertion, alternation, or congruent

lexicalization. These theoretical classifications help explain how students blend languages

during classroom communication, supported by recent studies emphasizing bilingual

flexibility in learning environments (Zhou & Chen, 2023).

Although many studies have explored bilingual behavior in informal domains such as

social media, peer conversations, and entertainment, fewer have examined bilingual practices

within academic settings. Classroom-based research has mainly focused on teachers' code

switching as an instructional strategy, while the bilingual behavior of students remains

& Brown, 2020; Lin & He, 2022).

Students’ use of code switching and code mixing in group discussions, peer interactions,

and classroom tasks also fulfills important communicative and pedagogical functions.

Gumperz (1982) notes that code switching can serve conversational functions such as

personalization, clarification, and topic shift. In the context of EFL classrooms, these

functions help students manage anxiety, maintain participation, express identity, and support

collaborative learning. More recent findings strengthen this view by showing that bilingual

practices encourage engagement, scaffolding, and cognitive processing in foreign language

learning (Li, 2021; Qiu & Han, 2023). Code mixing similarly reflects learners’ attempts to

demonstrate partial mastery of English while relying on their first language as a cognitive

incorporates contemporary perspectives from post-2020 research to highlight how students’

linguistic choices contribute to comprehension, engagement, and communicative efficiency.

The findings are expected to enrich sociolinguistic research in multilingual classroom

contexts and offer pedagogical implications for English teachers in Indonesia. Ultimately,

recognizing students’ bilingual practices as valuable resources can lead to more supportive

and effective English learning environments.

A descriptive qualitative approach was employed. The participants were 25 English

education students from the same class. Data were collected through classroom observations,

audio recordings of discussions and teacher–student interactions, and semi-structured

interviews. Analysis followed Miles and Huberman’s (2014) interactive model: data

types of code switching as outlined by Poplack (1980). Each type reflects different levels of

bilingual proficiency, communicative needs, and classroom functions.

a. Intersentential Switching

Intersentential switching occurs when a speaker alternates languages between sentences or

clauses. This type requires relatively higher control of both languages because the switch

happens at grammatical boundaries.

Examples:

This shows a shift in communicative intent from planning to self-expression.

The student repeats the message in English to align with classroom norms. Here, switching

functions as a clarification and emphasis tool.

Intersentential switching frequently appeared when students sought clarification,

confirmation, or assistance. It reflects a boundary-shifting mechanism between L1 and L2,

supporting Poplack’s (1980) claim that language alternation at sentence boundaries indicates

functional bilingual use.

The verb submit and noun assignment are English insertions into Indonesian structure. This

shows reliance on English academic terms commonly used in university settings.

The verb save is embedded in Indonesian syntax. Indicates familiarity with digital/academic

English terminology.

Present (verb) is used within an Indonesian sentence. Reflects common code mixing in

academic presentations. This dominant pattern suggests that students have internalized many

English lexical items as part of academic discourse. According to Poplack, intrasentential

switching is typical of more proficient bilinguals because it involves grammatical integration

across languages.

c. Tag Switching

Tag switching occurs when bilingual speakers insert discourse markers, fillers, or short tags

from one language into another. This type does not require deep grammatical integration.

Examples:

The English tag right? is used to seek agreement. Reflects pragmatic switching for checking

confirmation.

I think functions as a softening device to reduce assertiveness. Shows how students use

English to negotiate politeness.

syntactic integration and is often used even by less proficient bilinguals. The students’ behavior

supports Poplack’s (1980) typology: Intersentential switching used for clarification, requesting

help, signaling uncertainty. Intrasentential switching is most frequent, showing academic

bilingualism. Tag switching used for interactional purposes and conversational flow. The

variation in these types demonstrates that bilingual competence among the 25 participants

ranges from functional to intermediate–advanced, affecting how each student alternates

between Indonesian and English.

Based on Muysken’s (2000) classification, the students produced three main types of code

mixing: Insertion, Alternation, and Congruent Lexicalization. Each type reflects different

Examples:

Conclusion (English noun) is inserted into an Indonesian structure. Shows reliance on

English academic terminology.

The verb upload is inserted into Indonesian syntax. Illustrates students’ familiarity with

Submit is used as a verb inside an Indonesian sentence frame. Demonstrates hybrid

academic language commonly heard in classrooms.

Insertion mixing appeared because many English terms especially academic or technical

vocabulary do not have efficient Indonesian equivalents or are more commonly used in

English. This supports Muysken’s notion that insertion reflects the borrowing of lexical items

to increase precision and efficiency in communication.

b. Alternation

A full English clause is inserted after an Indonesian command. Shows a shift in reasoning or

explanation.

Alternation between Indonesian instruction and English sequencing. Used to maintain

logical flow in task explanation.

used for immediacy or emphasis.

Alternation tends to occur among students with moderate proficiency, as it requires the

ability to produce full English clauses spontaneously. The pattern reflects students’ efforts to

maintain communication despite vocabulary or grammar limitations in each language.

According to Muysken, alternation is typical when both languages play relatively equal roles in

the discourse.

c. Congruent Lexicalization

Congruent lexicalization occurs when elements from both languages appear within shared or

overlapping grammatical structures. This type reflects deeper bilingual integration and is

common in informal or spontaneous interactions.

Miss functions as a verb aligned with Indonesian syntax. Shows shared grammatical space

between languages.

English adverb really inserted mid-sentence without grammatical disruption. Illustrates fluid

bilingual mixing.

contexts, such as casual peer talk before or after class. According to Muysken, this mixing

occurs when both languages coexist in the speakers’ mental grammar, and boundaries between

the two become less rigid.

These findings align with Muysken’s argument that bilingual speakers shift between

languages depending on: linguistic resources, communicative purpose, proficiency levels, and

contextual demands. Insertion dominated academic talk, alternation supported explanation and

reasoning, while congruent lexicalization characterized natural student-to-student interaction.

The thematic analysis revealed several key factors influencing students’ bilingual behavior.

These factors are consistent with Hoffmann (1991) and commonly observed in EFL classroom

intermediate-level learners who have not yet developed robust lexical access in the target

language. Several studies also confirm that lexical retrieval difficulty is one of the most

frequent triggers for code switching in EFL settings (Alharthi, 2022; Qodriani & Setiawan,

2021).

b. Comprehension Support

Switching was used to clarify meaning, confirm instructions, or restate complex ideas.

When encountering challenging content or unclear instructions, students shifted to Indonesian

to ensure accurate understanding. L1 served as a scaffold that helped them interpret L2 content

more reliably. This type of switching supported deeper comprehension and helped prevent

misunderstandings during classroom tasks. Research has shown that L1 use enhances

Switching here is not only linguistic but also relational—strengthening friendships, facilitating

humor, and creating a supportive group dynamic. Recent studies demonstrate that code

switching helps build peer cohesion, fosters collaborative learning, and reinforces shared

identity (Sert & Brown, 2020; Qiu & Han, 2023).

d. Classroom Comfort

Using Indonesian helped reduce anxiety, especially in formal speaking tasks or when

responding to the teacher. Because English is often perceived as more formal or demanding,

students may feel anxious when required to use it consistently. Switching to Indonesian

provided emotional relief and boosted self-confidence. This made students more willing to

participate, even if their English proficiency was not strong. Studies in EFL contexts similarly

instructional details efficiently. As a result, bilingual practices helped facilitate smoother task

management and clearer collaboration. This has been supported by task-based learning

research showing that L1 use enhances coordination and improves task completion (Méndez &

Cruz, 2021; Tran, 2022).

Overall, these factors indicate that switching and mixing are not merely signs of linguistic

limitations; rather, they represent strategic communicative tools that facilitate learning,

interaction, and participation. Current journal research continues to emphasize that bilingual

practices in multilingual classrooms contribute significantly to comprehension, engagement,

and collaborative learning.

The functions observed in this study align with the framework proposed by Gumperz (1982)

that L1 use enhances instructional support and improves understanding of L2 materials (Cenoz

& Gorter, 2022; Li, 2021). From a communicative perspective, switching between English and

Indonesian helped maintain conversational flow and ensured smooth interaction, particularly

when students struggled to express ideas in English. Journal studies confirm that bilingual

alternation enables learners to sustain dialogue and negotiate meaning more effectively in

group discussions (Qiu & Han, 2023; Setiawan & Qodriani, 2021).

Cognitively, students drew on Indonesian to process complex concepts, reduce cognitive

load, and make sense of abstract academic content. This is supported by research indicating

that L1 use facilitates cognitive processing and reduces linguistic strain during demanding

tasks (Alharthi, 2022; Zheng & Park, 2023). Socially, bilingual practices contributed to

academic confidence.

Students in the English classroom frequently used code switching and code mixing during

lessons. The dominant forms were intrasentential switching and insertion mixing, indicating

active bilingual processing. Switching and mixing were influenced by linguistic limitations,

comprehension needs, and social dynamics. They served essential functions in supporting

communication and learning. Teachers should strategically use bilingual practices to scaffold

understanding while encouraging the development of English proficiency.