Sociolinguistic Influences on Vowel Production in Imbabura Kichwa Speech

Background: This article explores how sociolinguistic variables such as gender, education, and language dominance affect vowel production in naturalistic Imbabura Kichwa (IK) speech, a language in contact with Spanish. Methods: The data for this study were drawn from 17 sociolinguistic interviews conducted entirely in Kichwa with bilingual Kichwa-Spanish speakers in the province of Imbabura. 4,708 vowel tokens were analyzed using F1 (height) and F2 (frontness) measurements. Linear mixed-effects models were used to assess the influence of social variables on vowel quality. Results: Vowel height and frontness differ significantly by language source: Spanish-origin vowels /a/, /i/, and /u/ were articulated higher than their Kichwa-origin counterparts. Education level was also a key factor: highly educated speakers exhibit significant differences in both height and frontness for the front vowels /e/ and /i/, whereas less educated speakers neutralize these vowels, preserving the traditional Kichwa tri-vocalic system. For back vowels /o/ and /u/, no significant differences were found in either height or frontness across education groups. Language dominance shaped vowel production. Kichwa-dominant speakers showed no significant differences in vowel quality, while balanced bilinguals and Spanish-leaning speakers maintained distinctions in height and frontness for /e/ and /i/ but not for /o/ and /u/, suggesting a partial integration of Spanish phonological features. Gender effects were consistent with cross-linguistic patterns: female speakers produced more fronted and lower vowels than male speakers. Conclusion: These findings indicate that vowel production in IK is undergoing change, influenced by education, language dominance, and gender. Younger, more educated, and Spanish-dominant speakers are shifting toward a Spanish-like five-vowel system, while older, less educated, and Kichwa-dominant speakers maintain a more traditional tri-vocalic system. This study contributes to our understanding of language change in contact settings and provides a diachronic reference point for future research on phonological evolution in Kichwa and other Indigenous languages in contact with Spanish.