A growing literature explores the representational detail of infants’ early lexical representations, but no study has investigated how exposure to real-life acoustic-phonetic variation impacts these representations. Indeed, previous experimental work with young infants has largely ignored the impact of accent exposure on lexical development. We ask how routine exposure to accent variation affects 6-month-olds’ ability to detect mispronunciations. Forty-eight monolingual English-learning 6-month-olds participated. Mono-accented infants, exposed to minimal accent variation, detected vowel mispronunciations in their own name. Multi-accented infants, exposed to high levels of accent variation, did not. Accent exposure impacts speech processing at the earliest stages of lexical acquisition.

We examined full-term and preterm infants’ perception of frequent and infrequent phonotactic pairings involving sibilants and liquids. Infants were tested on their preference for syllables with onsets involving /s/ or /ʃ/ followed by /l/ or /r/ using the Headturn Preference Procedure. Full-term infants preferred the frequent to the infrequent phonotactic pairings at 9 months, but not at either younger or older ages. Evidence was inconclusive regarding a possible difference between full-term and preterm samples; however, limitations on the preterm sample size limited our power to detect differences. Preference for the frequent pairing was not related to later vocabulary development.

This study tested infants’ ability to segregate target speech from a background of ecologically valid multi-talker speech at a 10 dB SNR. Using the Headturn Preference Procedure, 72 English-learning 5-, 9-, and 12-month-old monolinguals were tested on their ability to detect and perceive their own name. At all three ages infants were able to detect the presence of the target speech, but only at 9 months did they show sensitivity to the phonetic details that distinguished their own name from other names. These results extend previous findings on infants’ speech perception in noise to more naturalistic forms of background speech.