Evaluating importance of facial expression in american sign language and pidgin signed english animations

Animations of American Sign Language (ASL) and Pidgin Signed English (PSE) have accessibility benefits for many signers with lower levels of written language literacy. In prior experimental studies we conducted evaluating animations of ASL, native signers gave informal feedback in which they critiqued the insufficient and inaccurate facial expressions of the virtual human character. While face movements are important for conveying grammatical and prosodic information in human ASL signing, no empirical evaluation of their impact on the understandability and perceived quality of ASL animations had previously been conducted. To quantify the suggestions of deaf participants in our prior studies, we experimentally evaluated ASL and PSE animations with and without various types of facial expressions, and we found that their inclusion does lead to measurable benefits for the understandability and perceived quality of the animations. This finding provides motivation for our future work on facial expressions in ASL and PSE animations, and it lays a novel methodological groundwork for evaluating the quality of facial expressions for conveying prosodic or grammatical information.