Nonfluency

Nonfluency, in linguistics, refers to deviations from smooth, continuous speech that occur in spontaneous language use. It encompasses interruptions, hesitations, and repairs and is often contrasted with fluency, which emphasizes continuous, well-paced speech. Nonfluency is a common feature of everyday conversation and can be found in speakers of different ages, languages, and proficiency levels.

Common forms of nonfluency include filled pauses such as uh and um, silent pauses, repetitions or reiterations (I-I want to), prolongations (sooo), interjections, and self-corrections or revisions (I will go, no, I’ll stay). These elements can appear in any discourse and across genres, though their frequency and distribution may vary with context and individual differences.

Causes and contexts of nonfluency vary. It often reflects cognitive processes like planning speech, retrieving words, or reorganizing discourse, and can increase with cognitive load, fatigue, or time pressure. Nonfluency is widespread among second-language learners and bilingual speakers as they manage lexical access and syntax in real time. While nonfluency can indicate normal conversational strategy, persistent or unusually severe disfluencies may be associated with speech disorders such as stuttering or cluttering, though nonfluency alone is not a diagnosis.

Measurement and study of nonfluency involve transcription and analysis of speech samples. Researchers count disfluencies per unit of speech (e.g., per 100 words), examine pause length and placement, and categorize types of disfluencies. Transcription schemes used in research, such as SALT, standardize these conventions for comparability.

In summary, nonfluency describes natural, often momentary departures from fluent speech that arise from planning, retrieval, and discourse organization, and it plays a meaningful role in how spoken language is produced and perceived.