Whence the fuzziness? Morphological effects in interacting sound changes in Southern British English

The fronting of the high-back, /u:/ and /U/, as currently seen in Southern British English, is a rare opportunity to study two similar sound changes at different stages of their phonetic development: /u:/-fronting is a more advanced change than /U/-fronting. Since the fronting in both vowels is restricted from applying before a following final /l/, e.g. in words like fool or pull, we can exploit the difference in the phonetic advance- ment of /u:/ and /U/-fronting to illuminate the nature of `fuzzy contrasts', affecting vowel+/l/ sequences in morphologically complex words. As recent results show that /u:/-fronting is partially limited in fool-ing (but not in monomorphemes like hula), we ask whether similar morphological constraints affect /U/ followed by /l/ (e.g. bully vs. pull-ing). Simultaneously, we consider the question of what phonological generalisation best captures the interaction between vowel fronting, /l/-darkening, and morphological structure. We present ultrasound data from 20 speakers of SBE representing two age groups. The data show that morphologically conditioned contrasts are consistent for /u:/+/l/, but variable and limited in size for /U/+/l/. We relate these findings to the debate on morphology-phonetics interactions and the emergence of phonological abstraction.