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Open Access Knowledge and Scholarship

Date of Award


Culminating Project Type


Degree Name

English: Teaching English as a Second Language: M.A.




College of Liberal Arts

First Advisor

Ettien Koffi

Second Advisor

Edward Sadrai

Third Advisor

Lisa Loftis

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Keywords and Subject Headings

L2 Speech Intelligibility, Vowel Intelligibility, Masking Analysis, Acoustic Phonetics, Brazilian Portuguese-accented English, Just Noticeable Differences


This study describes Brazilian Portuguese-accented English vowels acoustically by relying on the measurements obtained from an instrumental analysis using Praat. The goal is to assess the intelligibility of vowels produced by Brazilian L2 speakers of English. The standard methodology that has been applied to studies of General American English (GAE) vowels is adopted for this study. However, instead of measuring the vowels in citation form, this study measures the acoustic correlates of vowels in running speech style, which is not often found in Brazilian Portuguese speech analysis. The dataset that serves as the basis of this analysis comes from the Speech Accent Archive website, by Weinberger (2015). The participants are twenty Brazilian Portuguese speakers: 10 females and 10 males. Eleven monophthong vowels of English were analyzed. The participants recorded themselves reading an elicitation paragraph in which the vowels occur. The feature extraction methodology used in the analysis consisted in isolating, annotating, and measuring a set of three different words. The extracted features are F0, F1, F2, F3, and F4, intensity, and duration. Just Noticeable Difference (JND) thresholds are used to determine whether Brazilian Portuguese-accented pronunciation of English vowels in running speech is intelligible to MN hearers. The acoustic vowel spaces are created from the formants F1 and F2. Based on Koffi’s (2019b) Acoustic Masking and Intelligibility (AMI) theory, the vowels produced by the Brazilian Portuguese speakers are analyzed internally and externally. The internal masking analysis shows how clearly the vowels produced by the Brazilian Portuguese speakers are perceived. The external masking analysis helps to determine if masking is found between the vowels produced by the Brazilian and GAE speakers. The discussion presented in this study is based on the measurements of 4,620 tokens. The pedagogical implications and applications are a result of the analyses. This study’s findings reveal that the kiss vowel [ɪ], the face vowel [e], the trap vowel [æ], the lot vowel [ɑ], the cloth vowel [ɔ], and the goat vowel [o] are the most problematic segments among Brazilian Portuguese speakers of English. It is recommended to focus on the pronunciation of [ɪ], [e], [æ], and [ɑ] as internal masking issues take pedagogical priority.



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