Feasibility study on synthesis of English vowels with a vocal tract mapping interface

This paper describes the synthesis of English vowels with a vocal tract mapping interface developed in our laboratory. This interface uses five vocal tract shapes that are located at apexes of a pentagonal chart in consideration of Japanese vowels. It allows users to configure the vocal tract shape corresponding to the location of the mouse pointer based on interpolation. Moreover, it has a function of the inverse estimation of the vocal tract from formant frequencies. Although the interface has been developed considering the Japanese vowels, whether English vowels can also be synthesized with this interface is an interesting topic for confirmation of its versatility. Therefore, we investigated the feasibility of producing English vowels ([ɑ], [æ], [ɔ], [ɛ], [ɝ], [i], [I], [u], [ʊ], [ʌ]) with the mapping interface. As the first step, we investigated that the mapping interface could estimate vocal tract shapes for the English vowels synthesized with the VowelEditor in Praat as test sounds. Furthermore, listening tests were conducted to examine whether the re-synthesized vowel sounds with the mapping interface were matched with the original vowel sounds by Praat. The experimental results showed that the mapping interface has a potential for producing English vowels.