Infant-directed
speech (IDS) produced in laboratory settings contains acoustic cues, such as
pauses, pitch changes, and vowel-lengthening that could facilitate breaking
speech into smaller units, such as syntactically well-formed utterances, and
the noun- and verb-phrases within them. It is unclear whether these cues are
present in speech produced in more natural contexts outside the lab. We
captured LENA recordings of caregiver speech to 12-month-old infants in
daylong interactions (N = 49) to address this question. We found that the
final positions of syntactically well-formed utterances contained greater
vowel lengthening and pitch changes, and were followed by longer pauses,
relative to non-final positions. However, we found no evidence that these cues
were present at utterance-internal phrase boundaries. Results suggest that
acoustic cues marking the boundaries of well-formed utterances are salient in
everyday speech to infants and highlight the importance of characterizing IDS
in a large sample of naturally-produced speech to infants.
