Toddlers from low-income and language-minority immigrant families are at risk for language difficulties due to early disparities in the quality of their home language environment. The present longitudinal study extends previous research by investigating nursery teachers' communicative modalities and functions, and their relations with the conversational responsiveness and vocabulary of 42 (50% F) equivalent low-income monolingual and bilingual toddlers. Communicative modalities and functions were coded from videotaped interactions between teachers and small groups of toddlers at 18, 24, and 30 months at nursery school. Vocabulary in the majority or societal language (Italian) was assessed at 30 months using teachers' reports. The results showed that teachers used bimodal utterances (gesture + speech) more with bilinguals than monolinguals from 18 to 30 months while the reverse was true for unimodal spoken utterances. Bimodal utterances and language scaffolding strategies promoted toddlers' communicative initiatives in both groups and were longitudinally associated with children's vocabulary at 30 months. These results show that the school context may act as a protective proximal environment for stimulating and favoring majority language acquisition from the earliest stages of development in children from low-income and language-minority families.