This article reviews the limitations of defining profound hearing impairment solely by reference to pure-tone audiograms. Instead, profoundly hearing-impaired children may be described as those whose ability to distinguish spectral features in speech is extremely poor, and for whom the gross intensity variations in the waveform envelope are the principal acoustic cues. Examples of pattern cues that are available to profoundly hearing-imparied children are presented through an optical analog, and the usefulness of these cues is shown with regard to vowel and consonant identification, word stress-pattern perception, and distinction among sentences that differ in number of syllables, pattern, intensity, or rate. Perception of speech material through vision (lipreading) and also through combined auditory and visual modes are described, with a discussion of articulatory and language factors that influence intelligibility. Instructional strategies are briefly reviewed as they relate to educational improvement of speech-perception abilities of profoundly hearing-impaired children and to the development of special sensory aids.