Real Time, Non-Invasive Measurements of Vocal Tract Resonances: Application to Speech Training

This study reports the detenninationin real time of the frequenciesofthefirsttworesonancesofthe human vocal tract from measurementsof the acousticimpedancespectrumof the tract in parallel with the external field. The measurementswere made using a broad band, frequency-independent acoustic current source, a microphone and a spectrum analyserwhich displaysthe acoustic impedancespectrum. The display provided real-time, visual feedback whereby subjects learned to imitate target vowel sounds without hearing them. Inexperiencedsubjects who used this feedbackproducedsounds that wereapproximatelyas well recognisedas those produced by the same subjects imitatingtargetvowelsoundsafter listeningto them. The recognitionrate improveswith the subjects' experiencein usingthe impedancefeedbacktechnique.This non-invasivetechnique could thus have possible applicationsin speechtrainingandlanguage teaching.