Introduction

Even casual observation reveals that language users sometimes have different ways of saying or signing the same thing. Variation may be realized at all different levels of a language. English, for example, contains numerous examples of variation in the lexicon. Some American speakers use the word couch, while others say sofa or davenport. American Sign Language (ASL) also exhibits many well-known examples of lexical variation. For example, a number of signs exist for the concepts BIRTHDAY, PICNIC or HALLOWEEN.

At the phonological level, variation exists in the individual segments that make up words or signs or in parts of those segments. For example, speakers of a wide range of English dialects sometimes delete the final consonant of words that end in consonant clusters such as test, round or past, the result being tes', roun' and pas' (Labov et al. 1968, Guy 1980). In ASL, phonological variation can be seen in all of the parts that make up signs – in the handshape, movement, location and palm orientation, and sometimes even in the nonmanual features that are part of sign production. The basic structure of these parts is discussed in other chapters of this volume.

Variation may also occur in the morphological and syntactic components of a language. For example, in African American Vernacular English (AAVE), the copula be is variably deleted, and the sentences He is my brother and He my brother both occur.