Detecting laterality and nasality in speech with the use of a multi-channel recorder

Phonetic studies of nasal and lateral sounds pose numerous obstacles to researchers because there are no unequivocal acoustic parameters indicating these types of articulation. Therefore, investigators resort to special systems dedicated to the investigation of nasality and electropalatography (EPG), which is the main accessible alternative to spectrographic analysis in studying lateral sounds. These systems are costly, often invasive and do not examine naturally produced speech. The present article shows how a multi-channel recorder may be used in detecting non-invasively both nasality and laterality in speech. The described system records video together with multi-channel audio and calculates spatial coordinates of sound propagation sources. Such a combination of audio and video data allows the researcher to establish if the release of an articulated segment is oral, nasal(ized) or lateral.