staRt: Enhancing Speech Treatment With Smartphone-delivered Biofeedback

Traditional articulation treatment involves providing auditory models and verbal descriptions of correct articulator placement, then cueing repetitive motor practice. Images and diagrams of the vocal tract can be used as visual aids; however, no real-time visual display of articulatory or acoustic information will be made available. Knowledge of performance feedback could describe either the desired articulator placement or the auditory quality of the target sound.

In visual-acoustic biofeedback treatment, the elements of traditional treatment (auditory models and verbal descriptions of articulator placement) are enhanced with a dynamic display of the speech signal in the form of the real-time LPC (Linear Predictive Coding) spectrum generated by the staRt app. Because correct vs incorrect productions of /r/ contrast acoustically in the frequency of the third formant (F3), participants will be cued to make their real-time LPC spectrum match a visual target characterized by a low F3 frequency. They will be encouraged to attend to the visual display while adjusting the placement of their articulators and observing how those adjustments impact F3. Knowledge of performance feedback will typically involve reference to the location of the third peak or 'bump' on the visual display.