Code-switching is a common phenomenon in bilingual communities, but little is known about bilingual parents’ code-switching when speaking to their infants. In a pre-registered study, we identified instances of code-switching in day-long at-home audio recordings of 21 French–English bilingual families in Montreal, Canada, who provided recordings when their infant was 10 and 18 months old. Overall, rates of infant-directed code-switching were low, averaging 7 times per hour (6 times per 1,000 words) at 10 months and increasing to 28 times per hour (18 times per 1,000 words) at 18 months. Parents code-switched more between sentences than within a sentence; this pattern was even more pronounced when infants were 18 months than when they were 10 months. The most common apparent reasons for code-switching were to bolster their infant's understanding and to teach vocabulary words. Combined, these results suggest that bilingual parents code-switch in ways that support successful bilingual language acquisition.

语码转换是双语社区的普遍现象，但对于双语父母在与婴儿交谈时的语码转换知之甚少。在一项预先注册的研究中，我们在加拿大蒙特利尔的 21 个法英双语家庭的全天家庭录音中发现了语码转换的实例，这些家庭在婴儿 10 个月和 18 个月大时提供录音。总体而言，以婴儿为导向的语码转换率很低，在 10 个月时平均每小时 7 次（每 1,000 个单词 6 次），在 18 个月时增加到每小时 28 次（每 1,000 个单词 18 次）。父母在句子之间的语码转换比在一个句子内更多；这种模式在婴儿 18 个月时比 10 个月时更为明显。代码转换最常见的明显原因是支持他们的婴儿 s 理解和教授词汇。综合起来，这些结果表明双语父母以支持成功双语习得的方式进行语码转换。