Abstract:
Objective: Voice characteristics can vary across languages due to distinct phonological and articulatory demands. However, limited research exists on how acoustic parameters differ when bilingual speakers switch between Farsi and English. This study aimed to compare the acoustic voice characteristics when Persian teachers of English languages switch between English and Farsi.
Methods: Thirty-eight English language teachers (30 females, 8 males, age range: 20-28 years) with Persian as their native language and minimum three years of English teaching experience participated in this study. Participants were selected through random cluster sampling. All participants were screened for voice disorders using the Voice Handicap Index (VHI). Voice samples were collected using both Farsi and English versions of the Consensus Auditory Perceptual Evaluation of Voice (CAPE-V) sentences in an acoustic-treated room. Recordings were made using Shure SM 58 microphone and Sony ICD-PX240 recorder, maintaining a 10-cm mouth-to-microphone distance. Acoustic analysis was performed using Praat software to measure source-related measures (jitter, shimmer, fundamental frequency, harmonics-to-noise ratio) and vocal-tract related measures (first, second, and third formant frequencies F1, F2 and F3).
Results: No statistically significant differences were found in source-related acoustic measures (jitter, shimmer, fundamental frequency, harmonics-to-noise ratio) between English and Farsi speech (p>0.05). However, vocal-tract-related measures (F1, F2, F3) showed significant differences between the two languages, with lower values during Farsi speech compared to English (p<0.05).
Conclusion: Findings demonstrated that bilingual speakers produced notably different voice patterns contingent on language and speech task, indicating that inter- and intra-speaker variability in speakers' vocal features can be attributed in part to language effects. These differences were primarily observed in vocal-tract-related characteristics rather than source-related characteristics, suggesting that articulation strategies, rather than laryngeal functions, vary between languages.