Generalizability of speechreading performance on nonsense syllables, words, and sentences: Subjects with normal hearing

Ninety-six adults with normal hearing viewed three types of recorded speechreading materials (consonant-vowel nonsense syllables, isolated words, and sentences) on 2 days. Responses to nonsense syllables were scored for syllables correct and syllable groups correct; responses to words and sentences were scored in terms of words correct, phonemes correct, and an estimate of visual distance between the stimulus and the response. Generalizability analysis was used to quantify sources of variability in performance. Subjects and test items were important sources of variability for all three types of materials; effects of talker and day of testing varied but were comparatively small. For each type of material, alternative models of test construction and test-score interpretation were evaluated through estimation of generalizability coefficients as a function of test length. Performance on nonsense syllables correlated about .50 with both word and sentence measures, whereas correlations between words and sentences typically exceeded .80.