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The Korean Association for the Study of English Language and Linguistics
[ Article ]
Korea Journal of English Language and Linguistics - Vol. 26, No. 0, pp.275-285
ISSN: 1598-1398 (Print) 2586-7474 (Online)
Print publication date 28 Feb 2026
Received 24 Sep 2025 Revised 26 Dec 2025 Accepted 02 Feb 2026
DOI: https://doi.org/10.15738/kjell.26..202602.275

Measuring Vowel Contrast Revisited

Ye-Yeong Han ; Joo-Kyeong Lee
(First author) MA student, Department of English Language and Literature University of Seoul ye0626ye@gmail.com
(Corresponding author) Professor, Department of English Language and Literature University of Seoul 163, Seoulsiripdae-ro, Dongdaemun-gu Seoul, Korea, Tel: +82-2-6490-2519 jookyeong@uos.ac.kr


© 2026 KASELL All rights reserved
This is an open-access article distributed under the terms of the Creative Commons License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study revisits the measurement of vowel contrast by evaluating the Pillai score with a sample-size-adjusted threshold (P95) as a categorical criterion. We examined the assumption that vowels are contrastive when the Pillai score exceeds the P95 threshold as derived from the Stanley and Sneller (2023)’s contrapositive. Six adjacent English vowel pairs (/i–ɪ/, /ɛ–æ/, /u–ʊ/, /ɑ–ɔ/, /ɑ–ʌ/, /ɔ–ʌ/) produced by 36 native speakers in two speech corpora were analyzed through MANOVA on normalized F1, F2, and duration. Pillai scores of six vowel pairs were calculated for each speaker and then converted to binary values (Pbin), coded as 1 if the score exceeded P95 and 0 otherwise. Results showed that /i–ɪ/ and /ɑ–ʌ/ consistently exceeded the threshold across all speakers, while the /u–ʊ/ pair exhibited the lowest rate of threshold achievement as found in 27 out of 36. This indicates that 27 native speakers did not produce these vowels contrastively, reflecting unstable phonemic status of the /u–ʊ/ pair. Logistic regression confirmed that all vowel pairs were significantly more likely to yield Pbin =1. We concluded that native speakers tend to produce vowel pairs contrastively, although some speakers exhibited merged productions for certain pairs. The application of the Pillai score with its P95 threshold to vowel contrast analysis provides a unified criterion for assessing vowel contrasts in English. This approach could be further applied in L2 contexts to eliminate the need for direct native-speaker comparison.

Keywords:

vowel contrast, MANOVA, Pillai, Threshold

Acknowledgments

This work was supported by the 2025 Research Fund of the University of Seoul for Joo-Kyeong Lee.

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