In the period between sole use of single words and majority use of multiword utterances, children draw from their existing productive capability and conversational input to facilitate the eventual outcome of majority use of multiword utterances. During this period, children use word combinations that are not yet mature multiword utterances, termed "successive single-word utterances" (SSWUs). The language development of five children, observed in play with their mothers, was studied longitudinally across the transitional period (age 1 ; 3 to 2 ; 0). Results demonstrate a common developmental trajectory from single words to SSWUs, formed with the support of conversation, to more independent SSWUs, and finally to majority use of multiword utterances. The children varied in the extent to which they produced SSWUs and whether they first produced across-turn versus within-turn SSWUs. Possible reasons for variability and why SSWU production may be important to the development of multiword utterances are discussed.