Gemination at the junction of phonetics and phonology

Tashlhiyt Berber has contrastive singleton and lexical geminate consonants in all positions. In addition, it has two types of phonologically derived geminates: concatenated and assimilated ones. Within CV phonology, geminates, including post-lexical ones, are represented as single melodic units associated to two prosodic positions. This study examines the way these abstract autosegmental representations are reflected in the phonetic details of speech production. In particular, it investigates two questions: what are the acoustic and articulatory differences between singletons and lexical geminates; and are there any acoustic differences between the three types of geminates. Results show that the primary correlate which distinguishes singletons from geminates is duration, even for voiceless stops after pause. This primary correlate is enhanced by additional correlates which are crucial to perception of absolute initial and final geminates. The comparison between the three types of geminates shows that they all display the same temporal values which supports the assignment of the same timing representation to these three types of geminates. However, while assimilated geminates, like underlying ones, are enhanced by additional acoustic attributes, concatenated geminates are not. Implications of these results for the general issue of geminate behaviour are discussed, with particular interest on geminate Ambiguity and geminate Inalterability.