1. Department of Allied Health Sciences, Division of Speech and Hearing Sciences, School of Medicine, University of North Carolina at Chapel Hill, NC, USA,
2. Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC, USA,
3. Department of Linguistics, School of Literature and Human Sciences, University of Tehran, Tehran, Iran, and
4. Craniofacial Centre, Department of Dental Ecology, School of Dentistry, University of North Carolina at Chapel Hill, NC, USA