Shizuo Hiki

Influence of palate shape on lingual articulation

Abstract In this paper, the present situation in Japan regarding development and application of the electro-palatography is reviewed. Then, data on lingual articulation with respect to personal differences and child characteristics are reported. These data were obtained by combining the three-dimensional measurements of the plaster casts of the hard palates of fifteen adults, thirty children, and two children at different dental stages, with the electro-palatographic observation of the lingual contact patterns with the hard palates of the adult subjects and four children during utterances of the Japanese consonants.

Acoustical analysis for voice disorders

Glottal sound waveforms were derived by an inverse filtering method from sustained vowels uttered by 217 patients of laryngeal diseases and by 20 normal speakers. Various parameters which indicate individual characteristics were extracted from autocorrelation function, correlograms of time series of fundamental period and peak amplitude in each fundamental period, and spectral envelope of the glottal sound waveform. Then, interdependency among the acoustical parameters and the relation between those and medical parameters utilized in diagnosis were examined by principal-component analysis. Using canonical analysis, classification of some laryngeal diseases was attempted based on those acoustical parameters.

Some properties of formant frequencies of vowels uttered by deaf and hard of hearing children

Formant frequencies of the five Japanese vowels uttered by 35 deaf and hard of hearing children were measured utilizing sound spectrograph. The distribution of the formant frequencies on the F1-F2 plane for each kind of vowel and the relation between the formant frequencies of the five Japanese vowels of each of the defective children were compared with those of 8 normal children. Based on a muscle contraction model of speech organs, those results were analyzed in terms of the nature of imperfection in articulatory movement.