Coordinated interpersonal timing in preverbal mother-child interactions is assumed to be one fundamental feature of interpersonal relatedness and the basis for parent-child bonding. The ubiquity of and early evidence for this phenomenon in ontogeny hint at its biological "prewiredness" and relevance for development. The quality of interpersonal timing in early preverbal parent-child interactions was hypothesized (and partially shown) to predict quality of attachment, level of cognitive functioning, and patterns of language acquisition. The aim of this study was to investigate the assumption of a facilitating effect of adequate interpersonal coordination (measured by quality of attachment) on the development of verbal communicative competence in children during the first stages of language development. On the basis of longitudinal data for 25 mother-child dyads, videotaped when the children were 17, 23, 30, and 36 months old in a free play and a short separation situation, it was investigated whether securely and insecurely attached children differ with respect to the amount of verbal contributions, their realization as alternating or simultaneous utterances, and the duration of intra-turn and inter-turn pauses. The results show that attachment was related to children's use of communicative competence especially in stressful situations, its development being paced by the age or maturation of the child.