Abstract
This paper describes vocal-tract models that we have developed and their applications in education in acoustics. First, we grouped the representative models into two major categories depending on their configuration: straight vs. bent. Then, within each category, we discussed the characteristics of each model in terms of its degree of freedom of movement. Subsequently, we review lectures using the vocal-tract models and report the results of tests and questionnaires carried out simultaneously with the lectures, some of which were re-evaluated in this paper. On the basis of the review, we further discuss how education should be carried out using the vocal-tract models, and we made the following conclusions: 1) the models are useful not only for education on sounds themselves but also for phonetic education; 2) it is important that appropriate models should be selected depending on specific purposes; and 3) it is necessary to continuously develop more models having different properties with wider variations in the future.
