The complex notion of the public/private distinction of social spheres has not been systematically investigated in sociolinguistics; particularly in the case of bidialectal kindergarten age children and how they construct their social lives around this distinction in a public environment such as that of school. No simple continuum can clearly illustrate the distinction between public and private since the dividing line between the two is discursively renegotiated and recreated. Hence, the distinction between the two is normally characterised by fluidity rather than stability. This is the case in educational settings where it is firmly institutionalised. In this study, the public/private distinction is analysed as a communicative phenomenon in kindergarten children's linguistic practices in two varieties. The data illustrate that young children separate their social spheres into "public" and "private" by skilfully employing linguistic variation. That said, the distinction children make between the two spheres is not always predictable, not only due to the instability in the boundaries that separate one sphere from the other but also due to differences in speakers' linguistic ideologies regarding the use of specific varieties in certain communicative practices.