Tarone distinguishes two types of language play: language play as fun in a Bakhtinian sense, or language play as rehearsal, in Vygotskyan terms.
Ludic or language play for fun is different from ordinary uses of language. It is
behaviour not primarily motivated by human need to manipulate the environment (and to share information for this purpose) and to form and maintain social relationships.
[…] Like fiction, play is a kind of carnival reality (of the kind described by Bakhtin, 1981), parallel to the real world but having its own meanings.
[…] Play is an exuberance of the mind.
Lantolf sees language play quite differently, citing Vygotsky:
For Vygotsky, play is not a means for the child to have fun. Rather, it serves a fundamental role in the child's development, because it creates a zone of proximal development in which the child 'always behaves beyond his average age' (Vygotsky, 1978)