チンパンジーの摩擦音構音の可能性：流体力学的観点からの考察

抄録

The possibility of production of sibilant fricative /s/ in chimpanzee is investigated by aeroacoustic experiments and simulations. The upper and lower jaw, tongue and lip geometries were extracted from CT images of a 9-yr-old chimpanzee. Then, each geometry was printed out with 3D printer and assembled to form the vocal tract with sibilant groove. The flow was inserted to the replica of chimpanzee and the far-field sound was measured by a microphone. In addition, the large eddy simulation of compressible flow was conducted on the same geometry to clarify the flow configuration inside the vocal tract geometry. Results of the experiments showed that frequency of the sound generated by the replica of chimpanzee was lower than that of /s/ pronounced by humans. The simulation showed that the sound source emerged mainly near the upper incisor surface, indicating that the difference of flow configuration and acoustic resonance in the lip cavity is the cause of the difference of sound between the chimpanzee and humans.