The purpose of this paper is to illustrate an aspect of the adaptive property of languages. While scholars have shown that expansion in function is correlated with expansion of the linguistic structure, I show that a loss of function by a language may entail a loss of a particular linguistic distinction. The data used to illustrate this point are drawn from the bilingual community of Cuzco, Peru. (Language contact, the adaptive property of languages, linguistic variation, linguistic change.)[1] An earlier version of this paper was presented at the AAA meetings, December 1975, San Francisco. I would like to thank Gillian Sankoff, William Kemp, Jonathan Kaye and Dell Hymes for their comments on a previous draft of this paper.