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To begin learning their language, infants must locate words in the speech signal. Some models of word discovery presuppose that the discovery process depends on identifying phonetic segments (phones) in speech. To test the plausibility of models arguing that infants can reliably categorize consonants in speech, adult native speakers were asked to identify the consonant in vowel-consonant-vowel sequences extracted from spontaneous English infant-directed speech. Listeners could consistently identify some instances of consonants (for example, correctly indicating that an /s/ was an /s/). But many tokens (about half) were not consistently identifiable. Performance was significantly worse for codas than onsets. Providing the full utterance context in low-pass-filtered form did not aid recognition, nor did familiarization with the talker. In a second task, listeners were barely above chance in guessing whether a consonant was a word onset or a word-final coda. Performance on infant-directed speech was not markedly better than performance on a comparison set of adult-directed speech consonants. Erroneous responses frequently had little systematic resemblance to the correct answer. The results suggest that it is not plausible that infants can parse most utterances exhaustively into strings of uttered speech sounds and feed those strings into a statistical clustering mechanism.
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Infant placement and language exposure in daily life
Abstract Children's daily contexts shape their experiences. In this study, we assessed whether variations in infant placement (e.g., held, bouncy seat) are associated with infants' exposure to adult speech. Using repeated survey sampling of mothers and continuous audio recordings, we tested whether the use of independence‐supporting placements was associated with adult speech exposure in a Southeastern U.S. sample of 60 4‐ to 6‐month‐old infants (38% male, predominately White, not Hispanic/Latinx, from higher socioeconomic status households). Within‐subject analyses indicated that independence‐supporting placements were associated with exposure to fewer adult words in the moment. Between‐subjects analyses indicated that infants more frequently reported to be in independence‐supporting placements that also provided posture support (i.e., an exersaucer) were exposed to relatively fewer adult words and less consistent adult speech across the day. These findings indicate that infants' opportunities for exposure to adult speech ‘in the wild’ may vary based on immediate physical context.
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- Award ID(s):
- 2042285
- PAR ID:
- 10525891
- Publisher / Repository:
- Infant and Child Development
- Date Published:
- Journal Name:
- Infant and Child Development
- Volume:
- 32
- Issue:
- 3
- ISSN:
- 1522-7227
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/icd.2405
