Experimentation to Clarify the Socio-Emotional Roles of Sentence-Final Particles in East Asian Languages
In today’s complex Japanese society, an increasing number of people may experience difficulty understanding language, causing several problems in their lives. In search of a solution, I am conducting experimental research on linguistic communication using electroencephalography (EEG; i.e., brain waves), functional magnetic resonance imaging (fMRI), and other techniques. This necessitates collaboration with researchers from a variety of disciplines, such as psychology, physiology, and psychiatry, to mention a few. My current research focus is on a wide range of sentence-final expressions found in East and Southeast Asian languages, including Japanese, Chinese, and Korean. For example, we native Japanese speakers often use the particles -ne and -yo at the end of sentences in conversation, like “Tanoshii-ne.” (meaning “It’s fun, isn’t it?”), “Wakatteru-yo.” (meaning “I understand, right?”), and so on, although the particles have no exact English equivalents. Despite the fact that these sentence-final particles have no substantive meaning because they are function words, they can elicit a variety of emotions in the listener, both pleasant and unpleasant, depending on context. In order to better understand what kinds of emotions listeners feel and how their brains react to such particles, my collaborators and I began a project to measure indices like fMRI, EEG, brain waves, and pupil dilation to examine the neural substrates for the socio-emotional functions performed by these sentence-final expressions.
In light of recent communication problems in Japanese society, I believe this project is urgent because it has long been assumed that Japanese people with autism spectrum disorders (ASD), a developmental disorder that affects communication and behavior, rarely use sentence-final particles, especially -ne, or use them unnaturally. However, it is unclear how such developmental disorders influence the atypical usage of -ne as a linguistic modifier of interpersonal relationships. The empirical findings on the psychological and neural bases for processing sentence-final particles by people with developmental disorders versus typically developed people will provide new insights into how we can use words to understand each other and accept inter-individual differences in communication styles within a society. While pursuing this objective, I am grateful for the admirable support of many researchers who have helped perform neuroscientific experiments.