Autonomy and linguistic status of nonspeech language forms

Nonspeech language forms, above all sign language and writing, are discussed with respect to phylogenesis, ontogenesis, and acquisition as well as with respect toneurophysiological and psycholinguistic processes. Speech has not been demonstrated to be phylogenetically or ontogenetically prior to gestural expression. Especially the evidence of the linguistic ability of deaf and deaf-blind people demonstrates that the various expression forms (delological forms) of language are neurophysiologically and psycholinguistically parallel. A terminology is proposed for the linguistic description of these forms.