This study examined prior qualitative differences in the process of the emergence of verb use in two sisters when they were each 12 to 24 months of age (the older sister is 2 years and 9 months older than the younger sister). Daily diaries on both children were kept by the mother, who noted emergent structure and vocabulary. Systematic Analysis of Language Transcripts (SALT) analyses of the data revealed a synchronous pattern of verb acquisition for the older sister and an asynchronous pattern for the younger sister. The form, meaning, and relational function of the older sister's verbs emerged simultaneously between 19 and 20 months of age. In contrast, the integration of the form, meaning, and function of verbs for the younger sister occurred as part of a gradual and incremental process of change in her language production. These results predict that individual differences in children's acquisition of verbs will occur and will co-vary with their chronological age and general approach to language acquisition. (MM)