Real-time clarification of esophageal speech using a comb filter

The only treatment for the terminal symptoms of the laryngeal cancer is to remove the larynx including vocal cords, which mean that the patient loses his voice. Esophageal speech is a method of speech production using an esophagus. An air inhaled in the upper esophagus generates the esophagus vibration to produce a belch-like sound that can be shaped into speech. Although this method has difficulties to be mastered, the voice is able to keep the individuality since the speech is generated by his own vocal organs. This paper introduces a software filtering algorithm which clarifies esophageal speech with the individuality preserved, together with user’s evaluations by questionnaires.