Graduation Semester and Year
Spring 2026
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Linguistics
Department
Linguistics
First Advisor
Ivy Hauser
Second Advisor
Naoko Witzel
Third Advisor
Daniel Scarpace
Abstract
This dissertation investigates how length of second language (L2) exposure shapes the phonetic relationship between the first language (L1) and the L2 in adult Arabic-English bilinguals. Focusing on the production of voiced stops /b/ and /d/, the study examines how L1 Arabic and L2 English interact within a shared phonetic system and how this interaction develops as a function of increasing L2 exposure. Building on the Speech Learning Model and its revised version (SLM, SLM-r), the study adopts a relational perspective in which L1 and L2 are not treated as independent systems, but as dynamically interacting components of a shared phonetic space.
The dissertation addresses three main questions: (1) what constitutes the phonetic baseline of Arabic stop production in monolingual Jordanian speakers, (2) how length of L2 exposure shapes L1-L2 phonetic interaction in an L2-dominant environment, and (3) whether similar exposure-related patterns emerge in an L1-dominant environment with more limited L2 experience. To address these questions, the analysis was conducted across three groups. First, a monolingual baseline was established, showing that Arabic voiced stops are consistently produced with prevoicing (negative VOT). Second, bilingual speakers residing in the United States demonstrated systematic L1-L2 phonetic merging as a function of L2 exposure, with Arabic stops becoming less prevoiced and English stops becoming more prevoiced over time. Third, bilinguals in Jordan showed evidence that increasing L2 exposure also gives rise to the same pattern (yet weaker) of L1-L2 phonetic interaction, despite exposure occurring primarily through non-native L2 input.
Taken together, the findings show that phonetic merging between L1 and L2 develops gradually as a function of L2 exposure and reflects interaction within a shared phonetic system. Length of L2 exposure emerges as a key factor capturing the development of this interaction over time, revealing how phonetic categories shift relative to one another within individual speakers. Importantly, the results suggest that L1 phonetic attrition is better understood as restructuring driven by L1-L2 interaction rather than as loss of the native language. The emergence of similar exposure-related patterns across environments further indicates that the same underlying process operates even under different input conditions, with differences arising in the strength and distribution of interaction rather than in its fundamental nature. These findings contribute to theoretical models of bilingual speech by clarifying how phonetic categories evolve over time and by demonstrating the value of within-speaker approaches for examining L1-L2 phonetic interaction.
Keywords
Phonetic attrition, L1-L2 phonetic interaction, Bilingualism, Speech production, Arabic-English, Speech Learning Model
Disciplines
Arabic Studies | Bilingual, Multilingual, and Multicultural Education | First and Second Language Acquisition | Phonetics and Phonology
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Smadi, Dema, "Phonetic Attrition as an Outcome of L1-L2 Phonetic Interaction: Effects of L2 Exposure in Arabic-English Bilinguals" (2026). Linguistics & TESOL Dissertations. 3.
https://mavmatrix.uta.edu/linguistics_tesol_dissertations2/3
Included in
Arabic Studies Commons, Bilingual, Multilingual, and Multicultural Education Commons, First and Second Language Acquisition Commons, Phonetics and Phonology Commons