Language play is commonly observed in young human children. Although t
he developmental significance of such play has yet to be precisely def
ined, it seems likely that language play facilitates cognitive, langua
ge, and social development. Play with sounds and sound structures has
also been observed in animals, raising the possibility that this type
of play serves important developmental functions in a number of specie
s. A comparative perspective is necessary if we are to better understa
nd the significance of language play in various species, including our
own. In turn, a comparative perspective should incorporate evolutiona
ry considerations, making an evolutionary theory of language play esse
ntial.