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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

Michael Schwartz

Third Advisor

Monica Devers

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

Phonetics, phonology, sounds, ESL


This study investigates several acoustic correlates of the phonetic realizations of [0] and [o] produced by Serbian speakers of English. The impressionistic phonetic transcriptions and aural perception accounts indicate that Serbians have difficulty pronouncing the English non-sibilant [0] and [o] segments accurately. It is reported (Dimitrijevic-Savic & Jerotijevic, 2011; Koffi, 2015a) that they substitute [t], [f], [s], and [ts] for [0]; and [d] and [z] for [o]. The present study uses an acoustic phonetic methodology to investigate how Serbians pronounce these two segments. Speech samples from seventeen native Serbian speakers are investigated. These samples are part of George Mason University Speech Accent Archive. The same text has been read by more than 2000 L2 speakers of English from all over the world. Spectrographic and acoustic measurements are provided for 11 words from the elicitation paragraph that contain the digraph represented in the IPA by [0] and [o]. Digraph represents the voiceless interdental fricative [0] in five of the 11 words. Words containing [0] in initial position are . The only word in text that ends with [0] is . The segment [o] appears six times in the paragraph, in three words. In it occurs in word initial position, but in it occurs intervocalically. The acoustic correlates of intensity, duration, VOT, and COG are examined for all 187 occurrences of . The results show that [0] is substituted by the voiceless dental stop [t] 49% of the time, by the affricate [tj] 7%, and 1 % by the flap [r]. The voiced [o] is substituted 70 % of the time by the voiced dental stop [d] and 1 % by [ts]. The acoustic measurements indicate that Serbian speakers rely on intensity more than duration and Center of Gravity in determining which segments to substitute for [0] and [o]. The substitute segments are all very similar in intensity with [0] and [o] in GAE.


Even though this work is recognized under my name, there are those without whom I would not have been able to finish. For their faith in me and support I give thanks.

First and foremost, the completion of this thesis would not have been possible without the constant support and advice from my mentor Dr. Ettien Koffi. I greatly appreciate his infallible guidance, continuous feedback, and friendly conversations during my graduate program and the thesis work. I am sincerely grateful for his faith - in me and for encouraging me to pursue further studies. I could not have asked for a better advisor and mentor.

Further, my sincerest thanks goes to the other members of my thesis committee: Dr. Michael Schwartz and Dr. Monica Devers. Their insightful comments and suggestions have helped me greatly with this research. In addition, a special mention goes to my parents who encouraged my goals throughout my schooling. Although we were far away, their love and pride was ever present.

Finally, for all the love, advice, and technical support I thank my beloved fiancé Dusan.



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