Vowel to vowel coordination, diphthongs and Articulatory Phonology

This dissertation aims to propose a model for vowel to vowel coordination within the theory of Articulatory Phonology, specifically the coordination of vowels traditionally described as belonging to the same syllable, i.e. diphthongs. The proposed analysis, while filling a theoretical void on the representation of diphthongs within a theory advocating the necessity of identity between the units of planning and the units of production, also correctly predicts empirical data, with specific application to Romanian and possible extensions to other languages.;The dissertation examines complex nuclei, as an instance of syllable complexity, extensively examining the Romanian phonological diphthongs /ea/ and /oa/. The goal is both to propose a theoretical Articulatory Phonology analysis of complex nucleus effects and to provide experimental evidence that such a proposal is warranted and preferable to alternative analyses. The theoretical question is whether complex nucleus effects can be predicted by a specific coordination pattern of articulation rather than result from syllable hierarchy.;The proposal is that Romanian phonological diphthongs (and potentially other cross-linguistic "complex moras/nuclei") are two vowels in synchronous coordination with each other. Whether the articulatory and acoustic output of this synchronous coordination provides information that betrays its complex status or not is determined by additional dynamical properties of the two vowel production actions themselves. If the two vowel actions have equal strength then potentially the two are completely blended into one, since they begin synchronously and there is nothing in the system to give one of the vowels more prominence. They will be equivalent to a single vowel intermediate between the two. If for reasons (such as stress) the two vowels end up having different strengths, they may produce an output that is distinct from a simple average of the two.;Extensive experimental evidence to support this proposal is provided from production, perception and articulatory modeling. The dissertation also suggests ways in which the approach proposed for analyzing Romanian diphthongs can be extended cross-linguistically.