Iskarous Khalil
Department of Linguistics, University of Southern California, Los Angeles, CA, United States.
Front Psychol. 2019 Nov 12;10:2395. doi: 10.3389/fpsyg.2019.02395. eCollection 2019.
A subtle property of speech gestures is the fact that they are spatially and temporally extended, meaning that phonological contrasts are expressed using spatially extended , and have a finite duration. This paper shows how this spatiotemporal particulation of the vocal tract, for the purpose of linguistic signaling, comes about. It is argued that local uniform computations among topographically organized microscopic units that either constrict or relax individual points of the vocal tract yield the global spatiotemporal macroscopic structures we call constrictions, the locus of phonological contrast. The dynamical process is a morphogenetic one, based on the Turing and Hopf patterns of mathematical physics and biology. It is shown that reaction-diffusion equations, which are introduced in a tutorial mathematical style, with simultaneous Turing and Hopf patterns predict the spatiotemporal particulation, as well as concrete properties of speech gestures, namely the pivoting of constrictions, as well as the intermediate value of proportional time to peak velocity, which is well-studied and observed. The goal of the paper is to contribute to Bernstein's program of understanding motor processes as the emergence of low degree of freedom descriptions from high degree of freedom systems by actually pointing to specific, predictive, dynamics that yield speech gestures from a reaction-diffusion morphogenetic process.
言语手势的一个微妙特性在于它们在空间和时间上是延展的，这意味着语音对立是通过空间上的延展来表达的，并且具有有限的时长。本文展示了为实现语言信号传递目的，声道的这种时空颗粒化是如何产生的。有人认为，在地形组织化的微观单元之间进行的局部统一计算，这些微观单元会收缩或放松声道的各个点，从而产生我们称之为收缩的全局时空宏观结构，即语音对立的所在位置。这个动态过程是一个形态发生过程，基于数学物理和生物学中的图灵模式和霍普夫模式。结果表明，以教程式数学风格引入的反应扩散方程，同时具有图灵模式和霍普夫模式，能够预测时空颗粒化以及言语手势的具体特性，即收缩的枢轴点，以及峰值速度的比例时间的中间值，这些都是经过充分研究和观察到的。本文的目标是通过实际指出从反应扩散形态发生过程产生言语手势的特定、可预测的动态过程，为伯恩斯坦将运动过程理解为从高自由度系统中出现低自由度描述的计划做出贡献。
