The perceptibility of long-distance coarticulation in speech and sign

This paper describes a cross-modality investigation of the perception of long-distance coarticulation. We present the results of a sign study investigating anticipatory location-to-location (LL) effects in American Sign Language (ASL), and compare these findings with results of analogous research on anticipatory vowel-to-vowel (VV) effects in English. While listeners in speech studies showed great sensitivity to coarticulatory effects, relatively little evidence of sensitivity to coarticulation was found among sign study participants, even for the closest-distance effects. This was the case for both signing and sign-naive subjects. In addition, deaf subjects’ results were not significantly influenced by their ages of acquisition of ASL. These results parallel those of earlier research finding that LL coarticulatory effects in ASL appear to be weaker than the coarticulatory effects that are present in speech, at least in the contexts examined here. The outcome of this perception study may thus be due to the apparent weakness of coarticulatory information in the sign signal relative to the speech signal: to the extent that such information is available, users will tend to make use of it, as appears to be the case in speech perception. Where such information is not generally available, users will be less accustomed to making use of it even in cases in which it is present