Spanish-accented English is Spanish to English-learning 5-month-olds

Infants use prosody to distinguish between rhythmically-distinct languages, but in multilingual settings infants often encounter speakers who learned one or more of their languages later in life. Late learners of a language typically carry over the timing of their L1 into their L2. Can infants tell when a single heavily-accented speaker switches between two rhythmically-distinct languages? Or do infants have difficulty tracking which language this person is speaking? Here, we address this question by examining 5-month-olds’ ability to discriminate native Spanish from English speech samples produced by either a L2 English speaker (Experiment 1) or a L1 English speaker (Experiment 2). Infants succeeded in discriminating the two languages in Experiment 2, but not in Experiment 1. This suggests that infants perceived the Spanishaccented English as more Spanish-like than Englishlike. These findings underscore the importance of considering real-world speaker-related language variability in models of infant speech perception and language development.