Introduction

If you look closely at any sign language, you will soon discover familiar local gestures – nods, hand signals, even facial expressions – embedded within the language stream. At least, these signs appear familiar. However, their meanings, and the way they are combined with other signs, differ in many ways from their gesture lookalikes. Evidently, the first signers of these languages adopted everyday gestures as raw materials and used them to build the language. Once the gestures became part of a language, their functions changed.

These functions go beyond basic vocabulary. Many researchers of sign languages have suggested that gestures from the ambient culture were a source of grammatical elements too (Newport & Supalla 2000, Casey 2003, Wilcox 2004). Studies comparing gestures with contemporary signs support such an account. For example, a Jordanian hand gesture meaning ‘wait a second’ appears to have been co-opted as a negative completive marker in Jordanian Sign Language (Hendriks, 2004), and a French gesture meaning ‘to go’ is the likely source of a future marker in American Sign Language (ASL) (Janzen & Shaffer 2002). There are nonmanual examples too: the raising of eyebrows often seen on the faces of English speakers when they produce conditional sentences appears to be the origin of the eyebrow raise required with conditional expressions in ASL (Pyers & Emmorey 2007), and common American head movements and body postures have apparently been reshaped into ASL markers of negation and role shift (McClave 2000, 2001).