How long can naturalistic L2 pronunciation learning continue in adults? A 10-year study

Abstract

We examined the naturalistic pronunciation development of two groups of L2 speakers over 10 years. Initially, 50 beginner ESL students participated in production tasks; despite attrition, the tasks were administered eight more times. Here we report listener judgements of accentedness, comprehensibility and fluency for the remaining six Mandarin and 12 Slavic language speakers at Year 10. Analyses of listener judgments of accentedness, comprehensibility, and fluency of utterances recorded at the 2-month, 1-year, 2-year, 7-year and 10-year points revealed that the Slavic language speakers improved in comprehensibility and fluency at each comparison point, while the Mandarin speakers’ results were variable; there was improvement in comprehensibility from Year 7 to Year 10, but only after worsening at earlier points. The Slavic language group showed improvement in accentedness several times, whereas the Mandarin group showed no improvement in accentedness at any point. The data were examined for individual differences in learning trajectories. Interview responses and a survey of language use were compared to participants’ trajectories. Some speakers showed steady improvement from Year 7 to Year 10, but the majority plateaued or regressed. We also elicited speakers’ views of their progress. The results are interpreted through Complexity Theory and the Willingness to Communicate framework. Suggestions are made for research and teaching interventions.

ABSTRAIT

Nous avons examiné longitudinalement le développement en contexte naturel de la prononciation en anglais L2 chez deux groupes de locuteurs: mandarin (LMA) et langues slaves (LSL). Au départ, les 50 participants ont réalisé les tâches de production, qui leur ont été passées huit fois de plus, sur une période de dix ans. Nous rapportons ici les jugements sur l‘accentuation, la compréhensibilité et la fluidité des locuteurs restant à la 10e année, après attrition au sein des deux groupes (LMA n = 6; LSL n = 12). Les données collectées aux années sept et 10 ont révélé que les

LSL ont amélioré leur intelligibilité et leur fluidité à chaque point de comparaison, tandis que les LMA présentaient une variabilité: une amélioration de la compréhensibilité de la 7e à la 10e année, après une détérioration lors de points de comparaisons précédents. Les LSL ont démontré une amélioration de l‘accent à plusieurs reprises, tandis que les LMA n’en ont montré aucune dans le temps. Les données ont été examinées pour déterminer des différences individuelles. Les réponses aux entretiens et une enquête sur l‘utilisation de la langue ont été comparées aux trajectoires des participants. Une amélioration constante a été observée de la 7^e à la 10^e année chez certains locuteurs, mais la majorité d’entre eux a plafonné ou encore régressé. Nous avons également sollicité l’avis des locuteurs sur leurs progrès. Ces résultats sont interprétés dans le cadre de « la volonté de communiquer ». Des suggestions sont offertes pour la recherche et les interventions pédagogiques.

PLAIN LANGUAGE SUMMARY

This longitudinal study involved collecting data from two groups of second language speakers (Mandarin and Slavic language speakers) over 10 years. We recorded picture narratives from the 2-month, 1-year, 2-year, 7-year, and 10-year points. Audio samples of 20–25 s were randomized and played to 20 listeners who rated them on three dimensions using 9-point scales: fluency (1 = extremely fluent; 9 = extremely dysfluent); comprehensibility (1 = easy to understand; 9 = extremely difficult to understand); and accentedness (1 = no accent; 9 = extremely strong accent). Analyses indicated that the Slavic language speakers improved in comprehensibility and fluency at each comparison point, while the Mandarin speakers’ results were variable: there was improvement in comprehensibility from Year 7 to Year 10, but only after worsening at earlier points. The Slavic language group showed improvement in accentedness at several times, whereas the Mandarin group showed no improvement in accentedness at any point. We then considered individual trajectories, in the light of the language contexts in which each participant was immersed. There was tremendous variability in learner progress, but interestingly, the person who had the best ratings at the outset was judged the best after 10 years. It is clear that each person’s individual circumstances had an effect on their productions in English. The trajectories also suggested that some individuals made consistent progress in comprehensibility and fluency from Year 7 to Year 10, demonstrating that naturalistic language learning, at least for these dimensions, can continue for a long time, depending on the individual’s personal circumstances. The richer the interaction opportunities, the better.

Keywords:

• Longitudinal
• pronunciation
• fluency
• comprehensibility
• individual differences

Acknowledgements

First and foremost, we thank those participants who allowed us to study their language development over 10 years. It was a privilege to know them. We are also grateful to the listener/rater participants at Brock University. NorQuest College, Metro College and Sacred Heart in Edmonton were the initial sites of data collection and we thank the administrators who facilitated our data collection there. We also thank Bruce Derwing, Beth Zielinski, Daphnée Simard, and Jenifer Larson-Hall for assistance with this paper. Two reviewers provided helpful critiques, as did the Editor, Masatoshi Sato. We appreciate the funding received from the Social Sciences and Humanities Research Council of Canada to conduct several rounds of data collection for this study.

Ethics approval

This study received ethics approval from the Research Ethics Board at Brock University.

Disclosure statement

The authors report no conflicts of interest in the conduct of this work.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Social Sciences and Humanities Council of Canada under Grants [#435-2020-1102, Ron Thomson, PI; #410-2010-151] and two earlier SSHRC grants, Tracey Derwing, PI.

Notes on contributors

Ron I. Thomson

Ron I. Thomson is a Professor of Applied Linguistics/TESL at Brock University, Canada. His research focuses on the development of L2 fluency and pronunciation, and computer-assisted pronunciation instruction. He is the creator of www.englishaccentcoach.com, a free web-based resource for training learners to more accurately perceive English vowels and consonants.

Tracey M. Derwing

Tracey M. Derwing is a Professor Emeritus of TESL at the University of Alberta and an Adjunct Professor at Simon Fraser University. Her interests are related to enhanced communication of L2 speakers and their interlocutors, as well as matters related to refugees, immigration and integration. In 2022, she co-authored The Routledge handbook on SLA and speaking, Second language pronunciation: Bridging the gap between research and teaching, and The evolution of pronunciation teaching and research.

Murray J. Munro

Murray J. Munro is a Professor of Linguistics at Simon Fraser University, where he carries out research in applied phonetics. His interests include speech intelligibility, L2 pronunciation and vowel acquisition. His recent book Applying Phonetics: Speech Science in Everyday Life is published by Wiley.