A magnetic resonance imaging study on the articulatory and acoustic speech parameters of Malay vowels.

Alireza Zourmand,Shaik Ismail Bux,Kwan Hoong Ng,Seyed Mostafa Mirhassani,Mehmet Bilgen,Mohd Amin Jalaludin,Hua-Nong Ting

doi:10.1186/1475-925x-13-103

Alireza Zourmand, Shaik Ismail Bux + Show 5 more

Open Access

https://doi.org/10.1186/1475-925x-13-103

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Abstract

The phonetic properties of six Malay vowels are investigated using magnetic resonance imaging (MRI) to visualize the vocal tract in order to obtain dynamic articulatory parameters during speech production. To resolve image blurring due to the tongue movement during the scanning process, a method based on active contour extraction is used to track tongue contours. The proposed method efficiently tracks tongue contours despite the partial blurring of MRI images. Consequently, the articulatory parameters that are effectively measured as tongue movement is observed, and the specific shape of the tongue and its position for all six uttered Malay vowels are determined.Speech rehabilitation procedure demands some kind of visual perceivable prototype of speech articulation. To investigate the validity of the measured articulatory parameters based on acoustic theory of speech production, an acoustic analysis based on the uttered vowels by subjects has been performed. As the acoustic speech and articulatory parameters of uttered speech were examined, a correlation between formant frequencies and articulatory parameters was observed. The experiments reported a positive correlation between the constriction location of the tongue body and the first formant frequency, as well as a negative correlation between the constriction location of the tongue tip and the second formant frequency. The results demonstrate that the proposed method is an effective tool for the dynamic study of speech production.

Highlights

The investigation of articulator shape during speech production can facilitate the understanding of the mechanisms of speech production
magnetic resonance imaging (MRI) scanning parameters and image acquisition protocol Medical ethic approval was obtained from University of Malaya Medical Center (UMMC) before conducting the experiments
In the study of speech articulation, MRI imaging yields helpful and precise information on the shape of articulators, as well as their position during speech production. Their dynamics can be appropriately investigated for the study of their temporal functions during articulation

Summary

Introduction

The investigation of articulator shape during speech production can facilitate the understanding of the mechanisms of speech production. According to the acoustical theory of speech production [1], understanding speech production requires consideration of the vocal tract as an acoustical tube as its cross-sectional area changes during the speech production process [2]. From the 1940s to the 1970s, a large number of radiography experiments were conducted to collect the data that revealed the shape of the vocal tract during speech production. For subsequent research on acoustic speech production, the collected data were employed to develop early analog models for articulation. In the succeeding decades, continued research coupled with the advent of computers resulted in remarkable advancements in modeling the articulatory and acoustic processes. Articulation models have been used to study the more complex aspects of modeling, such as the three-dimensional shape of the tongue and its movements [3,4,5,6,7,8,9,10]

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