Abstract
A critical issue in models of speech production concerns the modularity of processing: for example, can information from morphology influence the articulation of phonologically identical segments? A phenomenon that has the potential to help shed light on this question is what we term morpho-phonetic adaptation: systematic phonetic differences in identical segments patterning with morphological differences. Previous studies have been largely inconclusive, finding longer (enhancement) and shorter (reduction) duration of affixes, as well as null effects. The occurrence of morpho-phonetic adaptation for affixes suggests that morphological information can indeed influence segment articulation. However, to date, most studies have involved acoustic realisations in English. If it is the case that morphology interacts with phonetics, such morphological effects should also be observed in languages other than English. We also hypothesise that effects should also occur in articulatory realisations such as tongue movements. In the present study, we compared acoustic duration and tongue movements between two German suffixes -er [ɐ] and -t [-t]. We found that the suffixal -er [ɐ] was significantly longer in duration and significantly lower in tongue positions than its segmentally identical non-suffixal counterpart, and the lower tongue position could not be simply attributed to longer duration. Importantly, however, no effect of morphological status was found for -t [-t] for either duration or articulatory trajectory. These findings show that morpho-phonetic adaptation manifests in multiple cues and may depend on segment identity, with implications for models of speech production.