Development and evaluation of a 3-D virtual pronunciation tutor for children with autism spectrum disorders - Fig 4

The AOIs with a Front View (A) and a Profile View (B). They corresponded to the homolographic areas inside the dashed red rectangle, which were closely related to speech sound production (with syllable po [p‘o] as an example). The AOI with a front view mainly incorporates lip movement area, and the AOI with a transparent profile view in the 3-D tutor contains the movement of external and internal articulators (including mouth, tongue, teeth, jaw, and palate) and airflow change.