Modality and the Structure of Language: Sign Languages Versus Signed Systems

Abstract

AbstractSign language research provides an opportunity to evaluate proposed models of natural language from a different perspective—signed instead of spoken, seen instead of heard. This chapter views fully developed sign languages from the perspective of universal grammar (UG) by discussing the “design features” of a model of language that is intended to be universal for all languages. From this perspective, the capacity for language is simultaneously universal to all humans, varied across languages, and individual to each person’s own experience and learned grammar. The study of sign languages has made it clear that natural language is not the same thing as speech. The goal is to provide an explanation for the characteristics of natural sign languages that separate them from artificially created signing systems. With that goal in mind, it explains layering as a largely ignored design feature of natural language, illustrates how it works in various sign languages, and then considers the implications of its absence in signed English (SE). Spoken languages have more segmental/sequential options available, and layered options are less frequently used (but not missing). Sign languages are more likely to use simultaneous/layered options (however, not exclusively), and which options will be used and what functions they are assigned differ from language to language. What the study of sign languages tells us about “language” is that natural languages share certain design features, specifically those that maximize information coding in a way that permits efficient production, perception, and processing.