Speech Intelligibility in Classrooms: Specific Acoustical Needs for Primary School Children

Abstract

Classrooms for primary school children should be built to criteria based on children's speech intelligibility needs which in some respects – e.g. reverberation time – differ markedly from the traditional criteria for adults. To further identify why the needs of children and adults for speech perception are so different we have measured the ‘integration time’ of speech for adults and children using a novel technique to obviate the complicating effects of differing language. The results for children are significantly different than for adults (35 ms c.f. 50 ms) and recommendations for classroom design based on the children's requirements have been made. When groups of children engage in ‘co-operative learning’ activities in the classroom, the “cafe effect” produces a rising activity noise level. We suggest the Lombard Effect is responsible for this. Measurements show children are more susceptible to the effect and we have developed a prediction model for activity noise in a classroom.