A study was undertaken to explore the relationship of mothers' language to infant development in terms of the infants' development of sensorimotor intelligence. Specifically, the study chronicled the infants' advances in sensorimotor development from J. Piaget's Stage II to Stage III as a possible explanation for changes in maternal language. It was hypothesized that advancement of an infant from Stage II (primary circular reactions) to Stage III (secondary circular reactions) would precede any major shifts in the language of the mother and that changes observed in the mother's language would have to do with pragmatics rather than syntax or semantics. The subjects were three infants and their mothers. The infants were between eight and ten weeks old when the study began and were studied during interactions with their mothers for approximately five months. The findings confirmed both hypotheses. In addition, the results supported the existence of a link between cognition and language acquisition at an earlier stage than previously demonstrated and strengthened the argument of the Piagetian school that language and cognition are interdependent in development. (FL)