The Repository @ St. Cloud State

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

James Robinson

Third Advisor

Zengjun Peng

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

vowel intelligibility, acoustic correlates, Mandarin Chinese, masking analysis, acoustic distance, vowel space



The objective of this project is to investigate whether or not Mandarin speakers produce English vowels intelligibly. This research replicates the methodology used by Peterson and Barney (1952) and Hillenbrand et al (1995) in their studies of General American English and Midwest English. In this study, 20 Mandarin speakers of English (10 males and 10 females) are asked to read 11 words contain all 11 English phonetic vowels. The participants in the study are college-aged students studying at Saint Cloud State University. They are divided into 4 subgroups based on their genders Length of Residency (LOR) in the USA. The four subgroups are as follows:

  1. Five males with LOR < 1 year
  2. Five males with LOR > 1 year
  3. Five females whose LOR < 1 year
  4. Five females whose LOR >1 year

Their speech samples were recorded using the same laptop (Model: MacBook Air; System: OS X Yosemite; Version: 10.10.5). The acoustic phonetic software Praat (Boersma & Weenink, 2018) is used for data collecting and measuring. The data is annotated and collected manually. The acoustic correlates measured are: F0, F1, F2, F3, Duration, and Intensity.

F1 and F2 are mostly focused in this research because they are the most robust cues for assessing the intelligibility of vowels. These measurements are used to determine whether or not the vowels produced by the participants mask each other. Masking thresholds are based on Koffi (2017). The effect of masking on intelligibility is assessed using Catford’s (1987) Relative Functional Load calculations. Acoustic vowel spaces are created to help visualize how the various vowels produced by Mandarin speakers of English compare with those produced by their GAE counterparts. The analysis shows that intelligibility is severely compromised in the following vowel pairs: [ɪ] vs. [e], [u] vs. [ʊ], and [ɛ] vs. [æ].

Other vowel pairs are challenging but our data indicates that these are the vowels that the 20 participants have hard time producing irrespective of their LOR in the USA. Finally Pedagogical implications and applications are drawn for teaching these vowels to Mandarin speakers of English.


First of all, I would like to express my deepest and sincere gratitude to my thesis advisor Dr. Ettien Koffi for his patience, motivation, enthusiasm and professional knowledge. His guidance helps me in all the time of research and writing of this thesis. Without his help, this thesis would not have been possible.

I would like to extend my appreciation to my second thesis reader, who is also my graduate program advisor Dr. James Robinson for accepting me to the program and helping me throughout the years at SCSU. I am also deeply thankful to Dr. Zengjun Peng for agreeing to be my committee member and sparing time to my thesis.

Last but not least, I would also like to express special gratitude to my parents Chengzhou Ma and Yufeng Ma for their endless support and confidence in my accomplishment in Master’s study. I thank my mother for being my best friend over the years and especially for encouraging me in researching and writing this thesis.