The purpose of this study was to examine the effectiveness of two professional development models in increasing family child care providers' frequency of linguistic inputs in conversations with young children. The first professional development model consisted of a 10-h in-service training focused on supporting early language development. The second included the same 10-h in-service training program and mentoring. Providers and children at 48 family child care programs participated in this study. The family child care programs were randomly assigned to one of the two professional development models (i.e., training or training with mentoring) or to a control group. Audio recordings of the language environment were collected prior to the in-service training, at the completion of the in-service training, and at the completion of the mentoring. Hierarchical linear modeling was used to examine the average increase in the frequency of providers' use of linguistic inputs over three observations, conducted before training, immediately at the end of training, and 6 weeks after training. Results indicate that both forms of professional development increased linguistically stimulating inputs as compared to the control group. The professional development model including mentoring support was related to greater increases in providers' use of informational talk and teaching utterances over in-service training without mentoring. (author abstract)