For the linguist interested in typology and language universals, this paper suggests the usefulness of a taxonomy of copula and copula-like constructions in the world's languages and the elaboration of hypotheses of synchronic variation and diachronic change in this part of language. For the linguist interested in child language development, the paper repeats earlier suggestions (Ferguson 1964) that the notion of simplicity may be a useful one in accounting for the development of grammar in the child, repeats the point that baby talk is largely initiated by adults on the basis of existing patterns, and suggests further that the telegraphic style used by young children may in part be based on the fact that adults in their attempt to simplify their speech (i.e. use baby talk) tend to omit items such as the copula, prepositions, articles, and inflectional endings. For the linguist interested in pidgins and creoles, the most important suggestion of the paper is probably the view that the foreigner talk of a speech community may serve as an incipient pidgin. This view asserts that the initial source of the grammatical structure of a pidgin is the more or less systematic simplification of the lexical source language which occurs in the foreigner talk register of its speakers rather than the grammatical structure of the language(s) of the other users of the pidgin. (Author/AMM)