Co-vocalizations and inter-speaker silences were used to investigate the vocal engagements of six mother-infant dyads. Observed records of vocal behaviours were compared with records in which the vocal behaviours were randomized. The results indicated that there were significantly fewer co-vocalizations in observed than in randomized records; that the durations of inter-speaker silences following infant vocalization were significantly shorter in observed than in randomized records; and that the durations of inter-speaker silences following maternal vocalization were significantly longer in observed than in randomized records. These findings were interpreted as being consistent with the view that mothers attempt to engage their infants in turn-taking encounters, and that descriptions of such engagements in terms of conversational metaphors may be misleading in this regard.

Pathways to Prevention is a developmental prevention project focused on the transition to school in a disadvantaged multicultural urban area in Queensland. The project incorporates two elements: The Preschool Intervention Program (PIP) promotes communication and social skills related to school success; and the Family Independence Program (FIP) (parent training, facilitated playgroups, support groups, etc) promotes family capacity to foster child development. Using a quasi-experimental design (N ¼ 597), improvements in boys' but not girls' behaviours over the preschool year were found. FIP reached more than a quarter of the target population, including many difficult-to-reach families experiencing high stress. Case studies and other qualitative data suggest positive outcomes.

Global tendencies for the relative absence of covocalization (simultaneous talk) have been identified in both conversations between adult partners and conversations between mothers and their infants; in each case, the alternating mode in which one partner speaks at a time is predominant. The present investigation examined the timing of the partners' talk in mother-infant engagements over infant age to determine whether: (a) variations occur in the incidence of the alternating mode; and {b) variations occur in the extent to which the alternating mode predominates. Conversations involving a total of 48 mothers and their infants aged from o; 3 to 2; o were investigated at each of eight infant ages (o;3, o;6, o;o, 1 ;o, 153, 1 ;6, 1 ;Q and 2;o). The results indicated that, within a global tendency for the relative absence of covocalization, there was: (a) a curvilinear tendency for the incidence of covocalization to decrease over the first 18 months, and then to increase; and {b) a linear tendency for the extent to which the alternating mode predominates to increase over age. These changes are interpreted as reflecting the facilitative effects of covocalization in the case of young preverbal infants, and the need for the alternating, turn-taking pattern to pre-

The content of mothers' talk to their infants (informative/eliciting acts versus noninformative/non-eliciting acts) was examined in terms of whether utterances were timed to follow their infants' 'talk' after a brief silence interval (alternating mode of temporal patterning), or to overlap their infants' 'talk' (covocalizing mode of temporal patterning). A total of 2827 maternal utterances in 39 mother-infant dyads were collected at three-month intervals over infant ages 3 to 24 months. The results indicated that mothers consistently timed informative/eliciting acts in ways that resemble conversations between adult partners (i.e. informative/eliciting acts predominated in the alternating mode), and that the relative proportions of these acts increased significantly during the infants' first year. Corresponding decreases in the relative proportions of non-informative/non-eliciting acts occurred in conjunction with significant reductions in the use of covocalizing mode, and this trend continued in the infants' second year: whereas at 3 and 6 months non-informative/ non-eliciting acts were predominant in the covocalizing mode, at 15 and 18 months they were predominant in the alternating mode. It is argued that such changes in content and timing constitute stylistic adjustments in mothers' management of interactions at the local moment-to-moment level, and occur within the context of global transformations in the dynamics of such interactions as infants' communicative abilities develop.

This research was funded from an ARC research grant to Ross Homel, Gordon Elias and Ian Hay as the chief investigators with Mission Australia as the industry partner. The cooperation of Education Queensland is acknowledged, particularly that of Carmel Prothero and Ruth Ernst, the two developmental language teachers involved with this project.