Investigation of code-switching cost in a conversation task

Bilinguals commonly co-mingle their languages when speaking among other bilinguals, which is known as code-switching (CS). Previous studies of CS using laboratory tasks have been equivocal on whether CS is cognitively demanding, as measured by a time cost. Given that CS time costs could be inflated in laboratory tasks because of their unnatural task requirements, the main goal of this study was to examine CS time costs in a novel naturalistic conversational paradigm in a group of English (L1)-French (L2) bilingual speakers. Producing code-switches in naturalistic conversation was associated with a time cost, and the magnitude was comparable in both directions (English-to-French and French-to-English) although speakers more frequently switched from French-to-English. Thus even though bilinguals may code-switch for sociopragmatic or linguistic accessibility reasons, they experience a time cost when making a switch. There were no differences in CS time cost whether the code-switches involved insertions or alternations between languages. The findings support recent bilingual code-switching models which propose that CS engages cognitive control mechanisms and that these mechanisms are similar for insertions and alternations.