ABSTRACT
It is now widely recognized that deafness is compatible with normal language development, provided that deaf children are reared in a linguistic environment suitable for their sensory possibilities. This generally implies that language could be perceived through the visual modality. This is the case for visual-manual sign languages. A number of studies showed strong similarities between the formal characteristics, acquisition, and breakdowns of sign languages and spoken languages (see e.g., Bellugi, Poizner, ScKlima, 1989; Pettito <Sl Marentette, 1991; Poizner, Klima, <Sl Bellugi, 1987). Native signers also appear to rely on mental representations of signs in situations in which hearing subjects rely on speech phonological representations (see Marschark, chap. 3, this volume). For example, native signers use sign representations in a task of ordered recall
of signed stimuli (Hanson, 1982). Finally, the presentations of signed stimuli elicit electrophysiological responses in native signers similar to those elicited by written words in hearing subjects (Neville, 1991; Neville, Coffey, Lawson, Fischer, Emmorey, & Bellugi, 1997). Taken together, these data suggest that there are strong constraints on acquisition and processing of formal languages, and that these constraints are independent of the modality through which language is acquired.
