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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.914-929
ISSN: 1598-1398 (Print) 2586-7474 (Online)
Print publication date 31 Jul 2026
Received 11 Jun 2026 Revised 06 Jul 2026 Accepted 06 Jul 2026
DOI: https://doi.org/10.15738/kjell.26..202607.914

The Impact of Learner and Acoustic Variables on Foreign Accentedness in L2 English Vowels

Hyunah Baek ; Shinsook Lee
(First author) Assistant professor, Department of English Language and Literature Ajou University 206 World cup-ro, Yeongtong-gu Suwon-si, Gyeonggi-do, Korea hyunahbaek@ajou.ac.kr
(Corresponding author) Professor, Department of English Language Education Korea University 145 Anam-ro, Seongbuk-gu Seoul, Korea, Tel: +82-2-3290-2353 leesseng@korea.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

Foreign accents are typically slow to change, although the perceived strength of foreign accent is affected by many learner factors (e.g., initial L2 age, age of arrival [AOA] and length of residence [LOR] in L2-speaking environments, amount of L1/L2 use). Furthermore, foreign-accented speech deviates from native acoustic norms across diverse acoustic measurements (e.g., frequencies of the first formant (F1), the second formant (F2), the third formant (F3), and vowel duration). While most research on the perceived strength of foreign accent focuses on either learner variables or acoustic properties, this study investigates the impact of both learner (initial L2 age, AOA, LOR, and full-time equivalent [FTE] years of L2 input) and acoustic variables (F1/F2/F3 distances and vowel duration differences from native acoustic norms) on foreign accentedness in L2 English vowels with L1-Korean-speaking adults living in the U.K. Four native speakers of Standard Southern British English (SSBE) and 28 Korean learners produced 12 bVt English words (e.g., bit, bot). Four different native SSBE listeners assessed the perceived strength of foreign accent on a 7-point Likert scale. The productions of native speakers and Korean learners were subjected to acoustic measurements. The effects of learner and acoustic variables on foreign accentedness were statistically estimated with ordinal mixed-effects regression models. The results from learner variables showed that only the effect of LOR was significant. The results from LOR and four acoustic measures as well as two-way interactions of LOR and each acoustic variable showed that all main effects and LOR were statistically significant; shorter F1, F2, F3 distances and longer vowel durations led to a significantly weaker foreign accentedness. The interaction between F2 distance and LOR and that between duration difference and LOR were also significant, indicating that the impact of F2 distance and duration difference grew stronger with increased LOR. The results suggest that adult L2 learners were perceived as foreign accented as their acoustic measures deviate from native acoustic norms and that adult L2 learners’ foreign accentedness can be reduced as their LOR increases. The study further discusses the implications of the findings for L2 theories of phonological acquisition.

Keywords:

learner variables, acoustic variables, LOR, foreign accentedness, L2 vowels

Acknowledgments

This research was supported by the College of Education, Korea University Grant in 2026.

References

  • Arslan, L. and J. Hansen. 1997. Frequency characteristics of foreign accented speech. 1997 IEEE International Conference on Acoustics, Speech, and Signal Processing, 1123-1126. [https://doi.org/10.1109/ICASSP.1997.596139]
  • Bialystok, E. 1997. The structure of age: In search of barriers to second language acquisition, Second Language Research 13(2), 116-137. [https://doi.org/10.1191/026765897677670241]
  • Boersma, P. and D. Weenink. 2014. Praat: Doing phonetics by computer (version 5.3.61) [software]. Available online at http://www.praat.org/
  • Bohn, O. S. 1995. Learnability and vowel perception: A new view on transfer and developmental effects. Second Language Research 11(2), 156-177.
  • Bongaerts, T., C. Van Summeren, B. Planken and E. Schils. 1997. Age and ultimate attainment in the pronunciation of a foreign language. Studies in Second Language Acquisition 19(4), 447-465. [https://doi.org/10.1017/S0272263197004026]
  • Chan, K. and M. Hall. 2019. The importance of vowel formant frequencies and proximity in vowel space to the perception of foreign accent. Journal of Phonetics 77, 1-22. [https://doi.org/10.1016/j.wocn.2019.100919]
  • Cho, K., J. G. Harris and R. Shrivastav. 2005. Factors affecting the perception of Korean-accented American English. The Journal of the Acoustical Society of America 118(3), 1899. [https://doi.org/10.1121/1.4779929]
  • Christensen, R. H. B. 2019. Ordinal—Regression models for ordinal data (version 2019.12-10) [R package]. Available online at https://CRAN.R-project.org/package=ordinal
  • Derwing, T. M. and M. J. Munro. 2005. Second language accent and pronunciation teaching: A research-based approach. TESOL Quarterly 39(3), 379-397. [https://doi.org/10.2307/3588486]
  • Derwing, T. M. and M. J. Munro. 2013. The development of L2 oral language skills in two L1 groups: A 7-year study. Language Learning 63(2), 263-285. [https://doi.org/10.1111/lang.12000]
  • Flege, J. E. 1984. The detection of French accent by American listeners. The Journal of the Acoustical Society of America 76(3), 692-707. [https://doi.org/10.1121/1.391256]
  • Flege, J. E. 1987. The production of “new” and “similar” phones in a foreign language: Evidence for the effect of equivalence classification. Journal of Phonetics 15, 47-65. [https://doi.org/10.1016/S0095-4470(19)30537-6]
  • Flege, J. E. 1988. Factors affecting degree of perceived foreign accent in English sentences. Journal of the Acoustical Society of America 84(1), 70-79. [https://doi.org/10.1121/1.396876]
  • Flege, J. E. 1995. Second language speech learning: Theory, findings, and problems. In W. Strange, ed., Speech Perception and Linguistic Experience: Theoretical and Methodological Issues, 229-273. Timonium, MD: York Press.
  • Flege, J. E. and K. L. Fletcher. 1992. Talker and listener effects on degree of perceived foreign accent. Journal of the Acoustical Society of America 91(1), 370-389. [https://doi.org/10.1121/1.402780]
  • Flege, J. E. and O. S. Bohn. 2021. The revised speech learning model (SLM-r). In R. Wayland, ed., Second Language Speech Learning: Theoretical and Empirical Progress, 3-83. Cambridge: Cambridge University Press. [https://doi.org/10.1017/9781108886901.002]
  • Flege, J. E., D. Birdsong, E. Bialystok, M. Mack, H. Sung and K. Tsukada. 2006. Degree of foreign accent in English sentences produced by Korean children and adults. Journal of Phonetics 34, 153-175. [https://doi.org/10.1016/j.wocn.2005.05.001]
  • Flege, J. E., G. H. Yeni-Komshian and S. Liu. 1999. Age constraints on second-language acquisition. Journal of Memory and Language 41(1), 78-104. [https://doi.org/10.1006/jmla.1999.2638]
  • Flege, J. E., M. J. Munro and I. R. A. MacKay. 1995. Factors affecting strength of perceived foreign accent in a second language. Journal of the Acoustical Society of America 97(5), 3125-3134. [https://doi.org/10.1121/1.413041]
  • Floccia, C., J. Butler, J. Goslin and L. Ellis. 2009. Regional and foreign accent processing in English: Can listeners adapt? Journal of Psycholinguistic Research 38(4), 379-412. [https://doi.org/10.1007/s10936-008-9097-8]
  • Idemaru, K., M. Kato and K. Tsukada. 2021. Foreign accent in L2 Japanese cross-sectional study. In R. Wayland, ed., Second Language Speech Learning: Theoretical and Empirical Progress, 377-395. Cambridge: Cambridge University Press. [https://doi.org/10.1017/9781108886901.016]
  • Iverson, P. and B. G. Evans. 2009. Learning English vowels with different first-language vowel systems II: Auditory training for native Spanish and German speakers. The Journal of the Acoustical Society of America 126(2), 866-877. [https://doi.org/10.1121/1.3148196]
  • Kent, R. D. and C. Read. 2002. The Acoustic Analysis of Speech. New York: Singular Thomson Learning.
  • Kim, J. E. and D. Silva. 2003. An acoustic study of the American English pronunciation of recently arrived Korean adult immigrants. Language Research 39(3), 613-637.
  • Ladefoged, P. 2006. A Course in Phonetics. Boston, MA: Thomson.
  • Lee, S. S. and M. H. Cho. 2020. The impact of L2-learning experience and target dialect on predicting English vowel identification using Korean vowel categories. Journal of Phonetics 82, 1-20. [https://doi.org/10.1016/j.wocn.2020.100983]
  • Lee, S. S., J. K. Kang and H. S. Nam. 2022. Identification of English vowels by non-native listeners: Effects of listeners’ experience of the target dialect and talkers’ language background. Second Language Research 38(3), 449-475. [https://doi.org/10.1177/0267658320965648]
  • Lee, S. S., J. K. Kang, D. J. Shin and H. S. Nam. 2019. The effect of dialect experience and talker variation on Korean EFL listeners’ English vowel identification. Studies in Foreign Language Education 33(4), 1-27. [https://doi.org/10.16933/sfle.2019.33.4.1]
  • Lenneberg, E. H. 1967. Biological Foundations of Language. New York: Wiley. [https://doi.org/10.1080/21548331.1967.11707799]
  • Major, R. 2018. Foreign accent. In C. Chapelle, ed., The Wiley Encyclopedia of Applied Linguistics, 1-7. New York: Wiley. [https://doi.org/10.1002/9781405198431.wbeal0420.pub2]
  • Meador, D., J. E. Flege and I. R. A. MacKay. 2000. Factors affecting the recognition of words in a second language. Bilingualism: Language and Cognition 3(1), 55-67. [https://doi.org/10.1017/S1366728900000134]
  • Mora, J., J. Keidel and J. E. Flege. 2015. Effects of Spanish use on the production of Catalan vowels by early Spanish-Catalan bilinguals. In J. Romero and M. Riera, eds., The Phonetics-Phonology Interface: Representations and Methodologies, 33-54. Amsterdam: John Benjamins Publishing Company. [https://doi.org/10.1075/cilt.335.02mor]
  • Moyer, A. 1999. Ultimate attainment in L2 phonology: Critical factors of age, motivation, and instruction. Studies in Second Language Acquisition 21(1), 81-108. [https://doi.org/10.1017/S0272263199001035]
  • Munro, M. J. 1993. Productions of English vowels by native speakers of Arabic: Acoustic measurements and accentedness ratings. Language and Speech 36(1), 39-66. [https://doi.org/10.1177/002383099303600103]
  • Munro, M. J. 2003. A primer on accent discrimination in the Canadian context. TESL Canada Journal 20(2), 38-51. [https://doi.org/10.18806/tesl.v20i2.947]
  • Munro, M. J. and T. M. Derwing. 1995. Processing time, accent, and comprehensibility in the perception of native and foreign-accented speech. Language and Speech 38(3), 289-306. [https://doi.org/10.1177/002383099503800305]
  • Nagle, C. 2018. Modeling classroom language learners’ comprehensibility and accentedness over time. Proceedings of the 9th Pronunciation in Second Language Learning and Teaching Conference, 17-29.
  • Neville, H. J., D. L. Mills and D. S. Lawson. 1992. Fractionating language: Different neural subsystems with different sensitive periods. Cerebral Cortex 2, 244-258. [https://doi.org/10.1093/cercor/2.3.244]
  • Oganyan, M., R. Wright and E. McCullough. 2021. Comparing segmental and prosodic contributions to speech accent. In R. Wayland, ed., Second Language Speech Learning: Theoretical and Empirical Progress, 337-339. Cambridge: Cambridge University Press. [https://doi.org/10.1017/9781108886901.014]
  • Oyama, S. 1976. A sensitive period for the acquisition of a nonnative phonological system. Journal of Psycholinguistic Research 5(3), 261-283. [https://doi.org/10.1007/BF01067377]
  • Pierrehumbert, J. 2001. Exemplar dynamics: Word frequency, lenition, and contrast. In J. Bybee and P. Hopper, eds., Frequency Effects and the Emergence of Lexical Structure, 137-157. Amsterdam: John Benjamins Publishing Company. [https://doi.org/10.1075/tsl.45.08pie]
  • Piske, T., I. R. MacKay and J. E. Flege. 2001. Factors affecting degree of foreign accent in an L2: A review. Journal of Phonetics 29, 191-215. [https://doi.org/10.1006/jpho.2001.0134]
  • Porretta, V. and B. V. Tucker. 2012. Predicting accentedness: Acoustic measurements of Chinese-accented English. Canadian Acoustics 40(3), 34-35.
  • Porretta, V., A.-J. Kyröläinen and B. V. Tucker. 2015. Perceived foreign accentedness: Acoustic distances and lexical properties. Attention, Perception, & Psychophysics 77, 2438-2451. [https://doi.org/10.3758/s13414-015-0916-3]
  • R Core Team. 2023. R: A Language and Environment for Statistical Computing (version 4.2.1) [software]. Available online at http://www.R-project.org/
  • Rizopoulos, D. 2022. Latent Trait Models under IRT (version 1.2-0) [R package]. Available online at https://github.com/drizopoulos/ltm
  • Saito, K. and A. Tierney. 2025. Roles of domain-general auditory processing in second language speech learning revisited: What degree of precision makes a difference? Language Learning 75(S1), 1-42. [https://doi.org/10.1111/lang.12722]
  • Svartvik, J. and G. Leech. 2006. English: One Tongue, Many Voices. Basingstoke, Hampshire, U.K.: Palgrave MacMillan. [https://doi.org/10.1057/9780230596160]
  • Trofimovich, P., S. Kennedy and J. Foote. 2015. Variables affecting L2 pronunciation development. In M. Reed and J. Levis, eds., The Handbook of English Pronunciation, 353-373. Hoboken, NJ: John Wiley & Sons. [https://doi.org/10.1002/9781118346952.ch20]
  • Van Engen, K. J., M. Baese-Berk, R. E. Baker, A. Choi, M. Kim and A. R. Bradlow. 2010. The Wildcat corpus of native- and foreign-accented English: Communicative efficiency across conversational dyads with varying language alignment profiles. Language and Speech 53(4), 510-540. [https://doi.org/10.1177/0023830910372495]
  • Wells, J. 1982. Accents of English, vol. 2. Cambridge: Cambridge University Press. [https://doi.org/10.1017/CBO9780511611759]
  • Witteman, M. J., A. Weber and J. M. McQueen. 2013. Foreign accent strength and listener familiarity with an accent codetermine speed of perceptual adaptation. Attention, Perception, & Psychophysics 75(3), 537-556. [https://doi.org/10.3758/s13414-012-0404-y]
  • Yang, I. Y. 2021. Differential contribution of English suprasegmentals to L2 foreign-accentedness and speech comprehensibility: Implications for teaching EFL pronunciation, speaking, and listening. Korean Journal of English Language and Linguistics 21, 818-836.