From potential to realization: an episode in the origin of language

What kind of input is necessary for a creature that has the linguistic pote ntial of a human being actually to realize that potential? Various scenario s are investigated on the basis of the empirical evidence available, includ ing feral children (who receive no input and do not develop language); and creoles, twin languages, and deaf sign languages (where it seems, clearly i n the case of deaf sign languages, only on certain approaches in the case o f creoles, that provision of a lexicon is sufficient for the development of a fully fledged language). It is concluded that provision of a lexicon - w ith as its initial stage the recognition that linguistic signs can be arbit rary - plays a surprisingly important role in the minimal requirements for linguistic development, and that cognitive prerequisites must be supplement ed by social ones.