This dissertation investigates language-specific acoustic and aerodynamic phenomena in language contact situations. Whereas most work on second language and bilingual phonology has focused on individual consonants and vowels, this project examines patterns of coarticulation in the two languages of Spanish-English and French-English bilingual speakers. These include speakers whose first language is either Spanish, French or English, and are late second-language acquirers, and heritage speakers of Spanish, who are early second-language acquirers. I focus on subtly different coarticulation patterns between English and Spanish, including the extent to which vowels are nasalized in contact with nasal consonants (Chapter 2), are lengthened before voiced consonants (Chapter 3), and whose quality is affected before voiced consonants (Chapter 4). Whereas the existence of such effects can be taken as universal, the degree to which they are implemented varies from language to language, presumably contributing to what defines a ‘native accent.’ My work thus presents a novel method to investigate coarticulatory patterns. The theoretical question that I address in my dissertation is whether bilingual speakers can establish distinct coarticulatory patterns in their two languages in ways that are similar to those of monolinguals of the two languages.
A related question is to what extent learning both languages in childhood (as in the case of heritage speakers) facilitates separating the two phonetic systems. In Chapter 2, I study coarticulatory vowel nasalization in Spanish and English using pressure transducers and Generalized Additive Mixed Models to observe how nasal airflow changes over time. In Chapter 3, I focus on vowel length as a cue for voicing of the following consonant in two Romance languages (Spanish, French) and English, which show opposite patterns. Chapter 4 is about vowel formant displacement patterns across time and the effect of vocalic length in Spanish and English. In Chapter 5, I present a new phonological model, “The Bilingual Coarticulatory Model”, which describes coarticulation as malleable and adjustable cross-linguistically in bilingual speakers that possess a higher level of linguistic proficiency.
Results show that properties pertaining to vowel quality are easier to acquire than durational properties, which would go against some of the L2 literature on the acquisition of vowels. Native speakers of Spanish show native-like nasalization values in L2 English, yet only when the syllabic structure of sequences is shared. Heritage speakers show native-like results in both languages with regard to nasalization, and L1En speakers show an adjustment of onset of nasalization but not of degree of nasalization. Regarding duration, heritage speakers were the only group to completely separate the two coarticulatory systems, as the other groups showed cross-linguistic influence. Finally, regarding the dynamics of vowel formants, speakers transfer L1 patterns to the L2. Linguistic proficiency in the L2 was a significant factor to acquire coarticulatory patterns. In the case of heritage speakers, different findings were found depending on the variable under study.