Investigation of code-switching cost in conversation and self-paced reading tasks

Aims and objectives: Studies of code-switching (CS) in bilingual speakers using laboratory tasks have been equivocal on whether CS is cognitively demanding. The goal of this study was to examine time costs at the juncture of a CS in a more ecologically valid experimental paradigm. Methodology: English (L1)-French (L2) bilingual speakers performed two tasks. The primary experimental task was a novel paradigm that elicited voluntary code-switches in conversation with a bilingual interlocutor. A silent self-paced reading task was used to compare with a laboratory task with involuntary switches. Data and analysis: Intersyllabic durations (conversation task) and reading times (reading task) were analyzed. CS cost was the time difference between code-switches and matched non-switches. Cost-switching costs for each switch direction (English-to-French and French-to-English) and type of switch (alternations and insertions) were also compared. Findings: Code-switches in conversation were associated with a time cost, and the magnitude was comparable in both directions although speakers more frequently switched from French-to-English. In self-paced reading, switching costs were observed only for switches into the dominant language. Across both tasks, there were no differences in CS time cost between insertions and alternations. Originality: This study reports a novel measure of CS costs in conversation, intersyllabic duration, and provides a cross-task comparison in the same group of bilingual speakers to better inform theories of CS. Implications: Bilingual speakers experience a time cost when making voluntary switches in conversations. The symmetrical switch costs suggest that both languages have similar activation levels throughout the conversation, and the cognitive costs arise from the act of momentarily switching languages, irrespective of their dominance. In self-paced reading, cognitive costs arise from disturbing the status quo of relative activation-inhibition of each language adopted to perform the task. The comparable CS time cost for insertions and alternations suggests similar cognitive control and linguistic planning mechanisms for both types of switches.