Systematic Review of Literature on Speech Intelligibility and Classroom Acoustics in Elementary Schools.

Purpose: Good verbal signals and low background noise are key factors for all children to maximize understanding of what is being taught. Classroom shape, surroundings, and even furnishings change how the environment "sounds" and how speech is "heard" in the classroom. Classroom acoustics is perhaps one of the most important, but often least considered, factors when designing a classroom. This systematic review aimed to characterize the relationship between intelligibility of speech and room acoustics in elementary schools based on the available evidence.

Method: Eligible studies were identified using two computerized databases: PubMed and Scopus. In total, 23 publications met our inclusion criteria: (a) Participants must have been from elementary schools, (b) acoustic characterization of the classroom must have been provided, (c) intelligibility tests must have been performed, and (d) articles were written in English.

Results: After identifying the parameters and tests used to quantify the intelligibility of speech, the speech intelligibility scores were analyzed in relation with acoustical parameters found in the articles, particularly signal-to-noise ratio and speech transmission index. Our results highlighted the negative effect on intelligibility associated with poor transmission of the speech and poor classroom acoustics caused by long reverberation times and high background noise.

Conclusion: Good classroom acoustics is needed to improve speech intelligibility and, therefore, increase children's academic success.