Within the last decade, a number of bilingual education programs in the United States have begun incorporating bilingual instruction in English and Spanish to both Latino and non-Latino children together. This paper describes the educational and language ecology of one such bilingual program at the kindergarten level in a school in the school district of New Rochelle (New York). These educational programs are neither monolingual, nor bilingual in the traditional sense. Children are instructed half the time in English and the other half in Spanish. The use of each language is controlled by the administrators, being kept separate at all times by assigning each language to different classrooms or locations. However, despite these strict linguistic boundaries, the children cross these borders on daily basis, and so their linguistic performances show much hybridity, giving evidence of translanguaging (hybrid practices of languaging bilingually). In the case reviewed in this paper, translanguaging takes place across teacher and students in four ways: to mediate understanding (e.g. children’s translations and interpretations to mediate with others and oneself); to construct meaning (when children make use of the language not being used in instruction); to include (being responsive to perceived interlocutor’s dominant language); to exclude (e.g. other children from interaction) and show knowledge (e.g. by trying out the words they know). It is concluded that the way (especially Latino) students appropriate the use of language illustrates a heteroglossic vision of bilingualism that occurs when Latino children of different generations and immigration histories, nationalities, race and social class, are educated jointly with non-Latino children.