Differences in the conversational characteristics of mothers of two-year-old twins and mothers of two-year-old singletons with older siblings were investigated. Three maternal conversational characteristics were examined: discourse features, illocutionary force features, and style parameters. The twins' and singletons' language skills were also compared and the relationship between the maternal conversational characteristics and language development scores was explored. The mothers of twins were found to differ significantly from the mothers of singleton children in their conversational behavior. The twin children were found to score significantly lower than the singleton children on measures of language expression and comprehension. Significant correlations were found between the maternal input features and the children's language scores. It is proposed that twins receive less responsive and less conversation-eliciting maternal speech. The possibility is offered that this style of speech may play a role in their slower rate of language development.