Objective: To determine the effectiveness of vowel centered accent modification (VCAM) on percent vowels correct in Mandarin-speaking Chinese pilot candidates at the word, phrase, and semi-structured speech levels to increase the likelihood of pilot candidates passing International Civil Aviation Organization’s (lCAO) Level 4 English Proficiency Requirement. Method: This was a single-subject changing criterion design with six participants. Three target vowels and one control vowel were selected for each participant. Mono and bisyllabic target words were selected from aviation textbooks recommended by the flight academy. Visual feedback and placement cues were provided to assist with each participant’s vowel productions. The Pierson Aviation English Questionnaire (PAEQ), a pre and post measure, was also administered. Results: All participants demonstrated gains in percent vowel correct (PVC) at the three levels of difficulty. All pilots reported decreased anxiety levels when speaking with native speakers, air traffic controllers, and flight instructors. All pilots reported increased self-confidence levels when using aviation phraseology and an increase in enjoyment when speaking English. Conclusion: This investigation was the first of its kind to evaluate the effectiveness of vowel centered accent modification in pilot candidates. It was also the first investigation to demonstrate the usefulness of skilled speech-language pathology intervention and the positive effect on improving intelligibility in second-language English speakers in aviation.
Keywords: vowel centered accent modification, accent modification, aviation, pilot, pilot candidates, speech-language pathology, spectrograms, traditional articulation therapy, Mandarin Chinese, English language leamer, English as a second language, changing criterion design, single-subject design, expanding the field
