Speech production acoustics in different language environment

在语音产生的研究中，对发音-声学关系的了解是一个关键因素。嘴唇是声道主要的声学控制点之一，因此了解其几何特征与声学特征之间的关系至关重要。为此，我们制作了一组法语受试者的唇形录像和石膏复制品，并对其进行了一组持续的元音和摩擦发音，采用双麦克风法测量了复制品的声辐射阻抗，并通过优化算法确定了单个均匀圆柱形管的长度和面积。结果表明，等效的声间面积与几何长度呈线性关系。本文采用三维有限元法对声道简化模型——声管的声学特性进行了数值模拟。结果表明了一些新的事实：如果壁阻抗分布的面积越宽或截面越平坦，则形成峰的频带宽度增加越多，在形成峰频率附近的声波振幅减小。日语元音的声道形状用核磁共振成像测量。我们通过使用我们的有限元模型来估计复杂形状的三维效果，其中我们引入了封闭部分的延伸系数。我们指出声道损失的影响只取决于横截面的周长。我们用机械激励的方法测量了一些情况下的声音传递函数，如打开/关闭声门和高/低音调。我们看到，对于喉部的修饰，灵敏度在高频区域更大。我们还用短时分析的方法分析了真实发音的元音，并讨论了上述影响。

In speech production research, a good knowledge of the articulatory-acoustic relationship is a key factor. As lips are one of the major vocal tract acoustic control points, it is of utmost importance to gain insight into relationship between their geometric and acoustic characteristics. Therefore, video recordings and plaster replica of the lips of a French subject were made for a set of sustained vowel and fricative articulations The acoustic radiation impedance of the replica was measured by a two-microphone method, and the length and area of a single uniform cylindrical tube were determined by a optimization algorithm. It has been shown that the acoustic equivalent interalabial area linearly depends on the geometric length.Acoustic characteristics of sound tubes as a simplified model of vocal tracts are simulated by a three dimensional Finite Element Method (FEM). The results suggested some new facts as follows ; if the area of the wall impedance distribution is spread or the cross section is flattened more, then the formant band widths are increase more, and the amplitude of sound wave is decreased near formant frequencies.The vocal tract shapes of Japanese vowels are measured by MRI.We estimated the 3D effect from the the complex shape by using our FEM models, in which we introduced an elongation factor for the closed section. We pointed out the effect of losses in the vocal tract which depends only on the circumference of the cross section. We measured vocal transfer functions by using mechanical excitation for some cases such as open/close glottis and high/low pitch. We saw that the sensitivity is larger in the high frequency region for the modification of the laryngeal part. We also analyzed real uttered vowels by using our short-time analysis, and discuss the above effects.