Summarizing research activities from October 1978 to August 1979, this is the fifth annual report of research on speech processing conducted in the Department of Psychology at Indiana University. The report includes extended manuscripts, short reports, progress reports, and information on instrumentation developments and software support. The report contains the following 15 articles: "Some Measures of Intelligibility and Comprehension" (D. B. Pisoni); "Discrimination of Relative Onset Time of Two-Component Tones by Infants" (P. W. Jusczyk and others); "Infants' Discrimination of Full and Partial Cues to Places of Articulation in Stop Consonants" (A. Walley); "Some Experiments on Perceptual Learning of Mirror-Image Acoustic Patterns" (M. E. Grunke and D. B. Pisoni); "On Set-Induction in Sentence Perception" (R. E. Remez and others); "Some Perceptual Dependencies in Speeded Classification of Vowel Color and Pitch" (T. D. Carrell and others); "Adaptation and Contrast in the Perception of Voicing" (J. R. Sawusch and P. Jusczyk); "Some Remarks on the Perception of Speech and Nonspeech Signals" (D. B. Pisoni); "Continuous Spectral Change as Acoustic Cues to Place of Articulation" (D. Kewley-Port); "Individual Infants' Discrimination of VOT: Evidence for Three Modes of Voicing" (R. N. Aslin and others); "Effects of Early Linguistic Experience on Speech Discrimination by Infants: A Critique of Eilers, Gavin and Wilson (1979)" (R. N. Aslin and D. B. Pisoni); "Fundamental Frequency as a Cue to Postvocalic Voicing: Some Data from Perception and Production" (T. M. Gruenenfelder); "Measuring Lexical Access during Sentence Processing" (M. A. Blank); "Speech Perception Laboratory: Current Computer Resources" (J. C. Forshee); and "SPECTRUM: A Program for Analyzing the Spectral Properties of Speech" (D. Kewley-Port). Lists of publications and of laboratory staff and personnel conclude the report. (SR)