Noun bias in maternal speech to one-year-olds.

This study examines the distribution of nouns and verbs in maternal speech to one-year-olds. Mothers and children were videotaped during toy play and non-toy play. Nouns and verbs in maternal speech were coded for frequency, sentence position and occurrence with grammatical inflections. Maternal speech was also coded for utterances that prompted the child to produce a noun or a verb. Frequency of nouns and verbs varied with context. There were more noun types and tokens during toy play, and more verb types and tokens during non-toy play. Nouns occurred more often than verbs in shorter maternal sentences, in sentence-final position, and with fewer grammatical inflections. Mothers also more often prompted their children to produce nouns. There was a significant positive correlation between frequency of noun types and tokens during toy play, and the proportion of nouns in children's first 50 words.