The thesis takes a new methodological lens to an old phenomenon by investigating successive child utterances from a conversation analytic perspective. It is theoretically significant that this phenomenon typifies the transition from single-word to constructed multi-word speech, and therefore signals the emergence of early grammar. Whilst past child language research has characterised the developmental emergence of the phenomenon, a conversation analytic (CA) perspective proves sensitive to questions of on-line emergence. The thesis reveals how successive child utterances are occasioned during the moment-by-moment activity of speaking and listening that constitutes child- adult discourse. The data comprise a longitudinal sample of audio- and video-recordings of three child- mother dyads at home during play, taken during the 16-22 month age period. By working in an analytical cycle of data observation and transcription, the study explicates individual instances in fine-grained detail. The inductive methods of CA uncover how a succession of child utterances is designed by both participants to constitute a moment of their ongoing sequence of interaction, and how these 'turns' are occasioned as opportunities for emergent grammar. A central finding is that the dyad construct their social context as one of talk-in-play- interaction and shape it into four patterns of turn organisation which are distinctly relevant to emergent syntax. Key to this process is the subtle deployment and integration of the participant's vocal resources (e.g. linguistic/prosodic utterance design), non-vocal resources (e.g. gesture, eye gaze) and physical resources (e.g. cultural objects of play). Opportunities to deliver a temporally successive next- utterance arise either as actions of doing further talk or re-doing prior talk with different implications for turn organisation. The study concludes that early grammar has a reflexive quality, both constructing a sequential environment for its own development and in turn being constructed by that environment.