Article published In: Linguistic Approaches to Bilingualism: Online-First Articles
Same vowels, distinct sounds
Phonetic differentiation in early Basque–Spanish bilinguals’ vowel production
Published online: 5 January 2026
https://doi.org/10.1075/lab.25054.li
https://doi.org/10.1075/lab.25054.li
Abstract
Previous research on bilingual speech production has mainly examined individuals whose first languages (L1s)
differ in vowel inventories, often focusing on individual vowels and revealing distinct phonetic realizations for cross-language
similar sounds. However, little is known about whether bilinguals with identical vowel inventories phonetically distinguish
between their two L1s. This study examined the acoustic characteristics of 38 Basque–Spanish early bilinguals’ production of the
vowels /a, e, i, o, u/ and tested whether code-switching frequency and amount of language use influence individual vowels and
vowel space in each language. The results showed that /i/ was lower and /i, o, u/ were more fronted in Basque than in Spanish. In
addition, bilinguals exhibited a larger vowel space in Spanish compared to Basque, with frequent code-switching diminishing this
difference regardless of language use. These findings provide updated acoustic norms for Gipuzkoan Basque and Northern Castilian
Spanish vowels and demonstrate that code-switching experience shapes phonetic realizations in early bilinguals whose L1s share
identical vowel inventories.
Article outline
- 1.Introduction
- 1.1Speech sound production in bilingual speakers
- 1.2The role of language use and code-switching frequency in bilingual speech production
- 1.3The current study
- 2.Methods
- 2.1Participants
- 2.2Materials
- 2.3Procedure
- 2.4Data coding
- 2.5Statistical analysis
- 3.Results
- 4.Discussion and conclusion
- Acknowledgements
- CRediT statement
- Data availability
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