A study of relationships between discrimination of accent and intonation, and hearing level in hearing-impaired children

Abstract

Language is something that is unconsciously acquired. In the case of hearingimpaired children, acquisition of speech and language is said to be delayed because their hearing inputs are limited. However, few studies have been able to explain the relationship between language acquisition and hearing level. This study analyzed the relationships between hearing discrimination of accents and intonations, and hearing levels in 64 hearingimpaired children. The results revealed that most of the children with less than about 85 dBHL could discriminate intonations, and children with less than about 70 dBHL could distinguish accents. The average gap in hearing level between children who could hear accents and those who could hear intonations was about 15 dBHL. The hearing level of children who could hear accents was lower than the hearing level of children who could hear intonations. In other words, severely hearing-impaired children could discriminate intonations more than accents. It is generally thought that intonations and accents in Japanese are distinguished by voice pitch variation, but this study suggests that some children discriminate intonations through information other than voice pitch (for example, utterance continuance time). The results indicate that intonations include various signals such as sound duration or shifts in sound pressures, and some hearing-impaired children can utilize this information when listening.