Sonagraphによるろう児および正常児母音の分析 : ろう・難聴児の音声に関する研究(1)

抄録

In order to know the abnormalities in the speech sounds of the deaf children, the experiments were performed to analyse with the Sonagraph the vowels of the deaf children and also as the control those of the normal hearing children. The following results were obtained: I. Concerning the pitches of vowels, (1) The individual differences of the pitches of vowels could be found either in the normal group or in the deaf group, but no significant difference could be ascertained between both groups by F-test. (2) Though there were negative correlations between the pitches and ages in both groups, the significant difference could not be found between the normal and deaf groups. (3) Among five vowels (a, e, i, o, u) the significant differences of the pitches was found in the normal group, but not in the deaf group. (4) the height of the pitches of vowels in the deaf group were in close correlation with the degree of hearing loss. As the hearing loss increased, the pitches of vowels decreased. II. Concerning the spectral of vowels, (1) The frequency regions of the formants in the normal group were higher than those in the group of normal adults. The differences in the spectra of vowels was found between the male and female group, but these differences were not so great as those found between the normal and deaf group. (2) The spectra structure of vowels was observed to be much influenced by the degree of hearing loss in the deaf group. The frequency regions of the formants of vowels were shifting to lower frequency region, and moreover the characteristic differences in the spectra among five vowels were decreasing. (3) In the deaf group with severe hearing loss, the individual differences in the spectra of vowels were remarkable, but the irregularities in the spectra were not always proportional to the degree of hearing loss. (4) As regards to the deaf children, whose hearing had been impaired after three years of age, it was noticed that the spectra of their vowels resembled to those of the normal hearing children.