Monolingual children were assigned to two groups to examine the role of reinforcement in language acquisition. One group was differentially reinforced for use of foreign vocabulary. The other group was first reinforced nondifferentially for use of either native or foreign language and later differentially reinforced for foreign language use. (PCB)

Videotaped conversations of Spanish-speaking children aged two or four years, first with their mothers and then with each other, were compared. Results support Vygotsky's hypothesis that children's skills in following regulations by others and in regulating others emerge in the social context of conversations. (PCB)

Evaluates the effects of presenting verbal models following the initiations or expressions of interest of 16 children aged 28 to 34 months on both production and comprehension abilities measures. Results suggest that the timing of exposure to language models plays a critical role in language acquisition. (RJC)

Results question the validity of Cummins's threshold hypothesis and suggest that degree of bilingualism is related to variability in cognitive measures only before a certain threshold of proficiency in the second language is attained. A cause-effect model in which degree of bilingualism appears as the causal factor affecting children's cognitive…