An ultrasonographic investigation of cleft-type compensatory articulations of voiceless velar stops.

Ultrasound imaging was used to investigate the articulation of the voiceless velar stop [k] in five speakers with compensatory articulation related to cleft palate. The perceptual evaluation of the acoustic realization and the visual assessment of the tongue movement for the target sound were made by three examiners. The analysis revealed a variety of different compensatory strategies that included glottal stops, pharyngeal stops, midpalatal stops and glottal and velar co-productions. One patient produced palatal click sounds together with a midpalatal stop. The ultrasound imaging also revealed covert articulatory movements that would have been missed in a purely perceptual analysis. The analysis of the ultrasound images points to subphonemic aspects of cleft-type compensatory articulation that are important to understand for speech therapy.