With the aim to advance our understanding regarding the role of the extended family interactional context for early mother-infant communication, we compared spontaneous early imitative exchanges in dyadic interactions between mothers and infants (Group 1, N = 26) who had no frequent contact with maternal grandmothers, to imitations in two familial subgroups (Group 2, N = 48): (a) dyadic interactions of infants with their mothers, and (b) with their grandmothers–persons who had frequent contact with the infant. Spontaneous dyadic interactions of infants with their mothers and grandmothers were video-recorded at home from the 2nd to the 10th month of their life. Both comparisons provided evidence of similar frequency of imitative exchanges and developmental trajectories of infant imitations, but also differences in the structure of imitation, the kinds of imitated behaviors and the temporal patterns of imitative components. In the frame of the theory of Innate Intersubjectivity, we assume that differential early family interaction may be related to variations in three fundamental dimensions of infant-significant other communication: “kinematics” (temporal patterns), “physiognomics” (spatial patterns or forms) and “energetics” (force or effort). These variations may affect the child’s ability for regulation and negotiation of interpersonal challenges within and outside the family context.