Understanding human speech production is of great interest from and engineering and linguistics perspective. Detailed knowledge about speech production gives rise to refined models for the speech signal that can be exploited for the design of powerful speech recognition, coding, and synthesis systems. Speech research may be conducted to address open questions in the areas of phonetics and phonology and is also important to understand language acquisition and language disorders. All of these efforts require intimate knowledge of the speech generation mechanisms. Imaging technologies such as X-ray, computed tomography (CT), ultrasound, and electromagnetic articulometry (EMA) have all been applied but have significant limitations. X-ray and CT involves exposure to ionizing radiation. Ultrasound probes obstruct natural motion of the jaw and visualize only one side of the airway. EMA sensors cannot be easily attached to deep articulators such as the paryngeal wall and velum. In contrast, MRI involves no ionizing radiation, is inherently 3D, and provides excellent visualization of soft tissue and soft tissue boundaries. However, MRI notoriously slow, and our group is focusing on developing methods for acquiring images in real-time (> 24 frames per second), which have enabled imaging of vocal tract shaping during free speech.
Selected References:
- W Chen, D Byrd, S Narayanan, KS Nayak. Intermittently tagged real-time MRI reveals internal tongue motion during speech production. Magnetic Resonance in Medicine. 82(2):600-613. August 2019. PDF JRNL
- Y Lim, Y Zhu, SG Lingala, D Byrd, S Narayanan, KS Nayak. 3D dynamic MRI of the vocal tract during natural speech. Magnetic Resonance in Medicine. 81(3):1511-1520. March 2019. PDF JRNL
- KS Nayak. Response to Letter to the Editor: “Nomenclature for real‐time magnetic resonance imaging”. Magnetic Resonance in Medicine. 82(2):525-526. August 2019. PDF JRNL
- SG Lingala, Y Zhu, YC Kim, A Toutios, S Narayanan, KS Nayak. A Fast and Flexible MRI System for the Study of Dynamic Vocal Tract Shaping. Magnetic Resonance in Medicine. 77(1):112-125. January 2017. PDF JRNL
- SG Lingala, BP Sutton, ME Miquel, KS Nayak. Recommendations for Real-Time Speech MRI. Journal of Magnetic Resonance Imaging. 2016, 43:28-44. January 2016. PDF JNRL MEDIA
- E Bresch, YC Kim, KS Nayak, D Byrd and S Narayanan. Seeing speech: capturing vocal tract shaping using real-time magnetic resonance imaging. IEEE Signal Processing Magazine 25(3):123-132. May 2008. PDF JRNL