Exploitation of morphological possibilities in signed languages

American Sign Language shares with spoken languages derivational and inflectional morphological processes, including compounding, reduplication, incorporation, and, arguably, templates. Like spoken languages, ASL also has an extensive nonderivational, noninflectional morphology involving phonological alternation although this is typically more limited. Additionally, ASL frequently associates meaning with individual phonological parameters. This association is atypical of spoken languages. We account for these phenomena by positing “ion-morphs,” which are phonologically incomplete lexical items that bond with other compatible ion-morphs. These ion-morphs draw lexical items into “families” of related signs.

In contrast, ASL makes little, if any, use of concatenative affixation, a morphological mechanism common among spoken languages. We propose that this difference is the result of the comparative slowness of movement of the manual articulators as compared to the speech articulators, as well as the perceptual robustness of the manual articulators to the visual system. The slowness of the manual articulators disfavors concatenative affixation. The perceptual robustness of the manual articulators allows ASL to exploit morphological potential that spoken language can use only at considerable cost.