Study of the voices of deaf children who received special education for the deaf by an oral method in the early Showa and Taisho era

Abstract

　A disk recording of voices of deaf children in the early Showa period under the title of “the results of the oral method in commemoration of the one-year anniversary of Osaka Deaf Oral School (created in 1927)”, was played back to analyze the formant frequencies of the speech of 9 deaf children and have 14 specialists perform auditory-perceptual voice evaluation. These 9 children had been educated by the oral method in the Taisho period, before the use of the auditory acuity method with hearing-aids. This record may be the oldest historical data of voices of the deaf, and may also have other historical value, in that Toru Kato has left data obtained from a residual hearing table carried out using audiometer 2A for the first time in Japan. The subjects had severe bilateral hearing impairments, which prevented them from acquiring adequate conversational skills. They were voices recorded after one-year training, but were still inferior in terms of differentiation of the formant frequencies (F₁, F₂) of the 5 vowel sounds. The above results revealed that a prototype efficacy of the oral method was developed in the early Showa and the Taisho period.