Shuster Linda I
Department of Speech Pathology and Audiology, West Virginia University, United States.
Brain Lang. 2009 Oct;111(1):66-72. doi: 10.1016/j.bandl.2009.06.003. Epub 2009 Jul 17.
There is no consensus regarding the fundamental phonetic units that underlie speech production. There is, however, general agreement that the frequency of occurrence of these units is a significant factor. Investigators often use the effects of manipulating frequency to support the importance of particular units. Studies of pseudoword production have been used to show the importance of sublexical units, such as initial syllables, phonemes, and biphones. However, it is not clear that these units play the same role when the production of pseudowords is compared to the production of real words. In this study, participants overtly repeated real and pseudowords that were similar for length, complexity, and initial syllable frequency while undergoing functional magnetic resonance imaging. Compared to real words, production of pseudowords produced greater activation in much of the speech production network, including bilateral inferior frontal cortex, precentral gyri and supplementary motor areas and left superior temporal cortex and anterior insula. Only middle right frontal gyrus showed greater activation for real words than for pseudowords. Compared to a no-speech control condition, production of pseudowords or real words resulted in activation of all of the areas shown to comprise the speech production network. Our data, in conjunction with previous studies, suggest that the unit that is identified as the basic unit of speech production is influenced by the nature of the speech that is being studied, i.e., real words as compared to other real words, pseudowords as compared to other pseudowords, or real words as compared to pseudowords.
关于构成言语产生基础的基本语音单位，目前尚无共识。然而，人们普遍认为这些单位的出现频率是一个重要因素。研究人员经常利用操纵频率的效果来支持特定单位的重要性。对假词产生的研究已被用于表明次词汇单位的重要性，如初始音节、音素和双音素。然而，当将假词的产生与真实词的产生进行比较时，这些单位是否发挥相同的作用尚不清楚。在本研究中，参与者在进行功能磁共振成像时，公开重复长度、复杂度和初始音节频率相似的真实词和假词。与真实词相比，假词的产生在大部分言语产生网络中产生了更大的激活，包括双侧额下回、中央前回和辅助运动区以及左侧颞上回和前岛叶。只有右额中回对真实词的激活比对假词的激活更大。与非言语对照条件相比，假词或真实词的产生导致了所有显示构成言语产生网络的区域的激活。我们的数据与先前的研究表明，被确定为言语产生基本单位的单位受到所研究言语性质的影响，即与其他真实词相比的真实词、与其他假词相比的假词或与假词相比的真实词。
