A multimodal corpus of speech to infant and adult listeners.

An audio and video corpus of speech addressed to 28 11-month-olds is described. The corpus allows comparisons between adult speech directed toward infants, familiar adults, and unfamiliar adult addressees as well as of caregivers' word teaching strategies across word classes. Summary data show that infant-directed speech differed more from speech to unfamiliar than familiar adults, that word teaching strategies for nominals versus verbs and adjectives differed, that mothers mostly addressed infants with multi-word utterances, and that infants' vocabulary size was unrelated to speech rate, but correlated positively with predominance of continuous caregiver speech (not of isolated words) in the input.

Lexical frequency and voice assimilation.

Acoustic duration and degree of vowel reduction are known to correlate with a word's frequency of occurrence. The present study broadens the research on the role of frequency in speech production to voice assimilation. The test case was regressive voice assimilation in Dutch.