Nonspeech

Nonspeech is a broad term used in linguistics, psychology, and related fields to denote sounds produced by the vocal apparatus or by environmental sources that do not constitute linguistic speech. The category encompasses human non-speech vocalizations such as laughter, crying, sighing, coughing, and throat clearing, as well as non-vocal sounds including environmental noises, musical tones, and mechanical sounds. In research and practice, nonspeech is typically contrasted with speech, which involves linguistically structured vocalizations used to convey meaning.

In practice, nonspeech serves multiple roles. It provides control stimuli for experiments in auditory perception, speech processing, and language development, helping to isolate cognitive and perceptual mechanisms from lexical content. Nonspeech also functions as a source of emotional and pragmatic cues, since many non-speech sounds carry information about speaker state, intention, or situation. Additionally, nonspeech stimuli are used to study sound source segregation, pitch and timbre processing, and prosody independent of linguistic structure.

Classification of nonspeech can be challenging because the boundary between speech and non-speech is not always clear. Some sounds may be integrated into speech systems as interjections, prosodic markers, or paralinguistic signals, while others remain clearly nonlinguistic. Researchers must specify criteria for what counts as nonspeech in a given study to avoid conflating perceptual or cognitive processes.

See also: speech perception, paralinguistics, phonetics, auditory processing, acoustic phonetics.