The purpose of the present study is to examine the pragmatic contexts in which nouns and verbs are used in speech to young children with analyzed the distribution of nouns and verbs in maternal and child speech and maternal speech acts. Participants were 24 mother-infant dyads. Their interactions in two contexts(toy-play and book-reading) were videotaped in their home and videotaped interactions were transcribed. The results of this study are as follows. First, mother's speech data show that mother focused verbs in toy-play contexts and nouns in book-reading contexts. But, infants speak significantly more noun types and noun tokens than verb types and tokens in both contexts. Therefore, present study support early predominance of nouns pattern. Second, When mothers elicit and reinforce children's verbal responses, they are far more likely to encourage the production of nouns than verbs. On the other hand, when mothers elicit and reinforce children's behavioral responses, they request children to perform actions more often than to identify objects. Moreover, mothers more often prompt children to produce an action than to produce a verb. This patterns appear regardless of ages and contexts. Speech acts analysis from the viewpoints of pragmatics indicate that expressive vocabulary analysis can not explain infant's overall language development. After all, this study's findings suggested that mother-infant's function-specific interaction play an important role in infant's language development.