Production and Perception of Vocalic Sequences in Mexican Spanish

This dissertation investigates variation in the production and perception of vocalic sequences in Mexican Spanish, with an emphasis on the relationship between this variation and the occurrence of exceptional hiatuses. The dissertation aims to demonstrate that:(i) The phonetic variation responsible for the occurrence of exceptional hiatuses is present in all Spanish varieties, including highly diphthongizing varieties (like Mexican Spanish). (ii) The phonetic variation leading to the production of exceptional hiatuses is rooted in patterns of articulation. (iii) Variation in the production of diphthongs, hiatuses and exceptional hiatuses is related to variation in their perception. Three studies were conducted to test these goals. The studies used a variety of experimental and statistical techniques (including duration and formant normalization procedures, electro-magnetic articulography, discriminant analysis, signal detection measures, and AX perception tasks) to provide and evaluate acoustic (Chapter 3), articulation (Chapter 4) and perception (Chapter 5) data. In support of the first and second goals, the acoustic and articulation results uncover sequence-specific and speaker-specific variation in the production of diphthongs and hiatuses, as well as the presence of exceptional hiatuses. The articulation results also offer evidence for the articulatory stability of diphthongs and tentatively suggest that the actions of the Tongue Tip (TT) are crucial for achieving the Diphthong-Hiatus contrast and for diphthongization. While the results of the perception study do not support the third research goal of establishing a production-perception link for vocalic sequences in Mexican Spanish, they reveal an unexpected, possibly dialect-specific Vowel effect which merits further investigation. Overall, the main findings of this dissertation support the idea that the occurrence of exceptional hiatuses stems from coarticulatory variation found in all Spanish varieties. These findings challenge the assumption of an underlying syllabicity contrast between diphthongs and exceptional hiatuses and question the need for a special category of exceptional hiatuses.Ph.D