Optical Phonetics and Visual Percep Stress in Eng

Three male American English talkers spoke words that differed in lexical stress, and sentences that differed in phrasal stress, while video and movements of the face were recorded. In a production study, stressed vs. unstressed syllables from these utterances were compared along many measures of facial movement, which were generally larger and faster. In a visual perception study, 16 perceivers identified the location of stress in forced-choice judgments of video clips of these utterances (without audio). Phrasal stress (54% correct vs. 25% chance) was better-perceived than lexical (62% correct vs. 50% chance). The relation of visual intelligibility to the optical characteristics of production is discussed.