‘Natural laboratories’

When people create a pidgin, they use as ingredients for it some of the words and bits of syntax of the language or languages that they know. This fact, noted in Section 5.2.5.2, lies at the root of one of the limitations of Bickerton's variant of the pidgin window on language evolution. The fact, that is, points to a clear dissimilarity between pidgin formation and the creation of the earliest language(s). After all, for the creators of the very first human language(s) there was no human language from which to derive ready-made components such as (proto)words and bits of syntax. This lends significance to reports of new linguistic systems whose creators have no language from which to derive components for these systems. The creators are deaf children of hearing parents who do not communicate with them in a conventional sign language. And these children create two types of new gestural systems: the first is referred to as ‘homesign’, ‘homesigns’ or ‘homesign systems’, and the second as ‘emerging sign languages’ or ‘emergent sign languages’. Homesign systems and the sign languages that emerge naturally from them, it is claimed, offer a better window on language evolution than do incipient pidgins. But how big is the heuristic potential of this analogue window? This is the general question to be addressed in this chapter.

The window potential of homesign systems and emergent sign languages has been recognised by two categories of scientists. In the first category, we find scientists who are primarily engaged in the study of homesign systems and/or emergent sign languages. The work of these scientists, that is, is not driven by questions about the evolution of language per se. But in pursuing their primary concerns, these scientists have realised that features of homesign systems and emergent sign languages may provide insights into language evolution. Thus, Susan Goldin-Meadow, a leader in this category, has expressed the view that – ‘[o]ur challenge is to discover the forces that shape gesture creation in deaf children – for these are the forces that are likely to play a role in language creation every time it takes place, perhaps even the very first time’ (Goldin-Meadow 2002: 369).