Assessment of sound laterality with the use of a multi-channel recorder

Acoustic analysis of laterality in speech sounds poses numerous obstacles to researchers. Spectral characteristics of such segments vary depending on their phonetic context and shaping of the vocal tract [1]. There are no unambiguous acoustic parameters indicating that a sound is produced laterally. The main alternatives to spectrographic analysis in studying laterality are costly devices, such as electropalatographs (EPG) and magnetic resonance imaging (MRI) scanners. This article demonstrates how a much more affordable device, the multi-channel recorder, may be used in detecting and assessing laterality in speech. The system records multi-channel audio and calculates spatial coordinates of sound propagation sources, allowing the researcher to establish if the release is central, unilateral or bilateral. This method allows also for evaluating the dominance of the release on the left or right side. It may be used in assessing nasality, too.