Overview

A consonant classified as a stop or plosive is produced by briefly closing the vocal tract so that airflow from the lungs is halted, then releasing that closure to create a characteristic burst or click of sound. The defining gesture is a complete obstruction followed by a release; during the closure no oral airflow passes. Stops are among the most common consonant types across the world's languages and appear in many different positions within words.

How stops are made

In descriptive phonetics, a stop is described by three basic components: the place of articulation where the blockage occurs, the manner of release that produces the burst, and the phonation (voicing) during the closure. Air pressure builds up behind the closure—often referred to simply as pressure—and that stored energy is responsible for the audible burst when the tract opens.

Places of articulation

  • Bilabial: both lips (e.g., English p, b).
  • Alveolar: tongue tip or blade against the alveolar ridge (e.g., t, d).
  • Velar: back of the tongue against the soft palate (e.g., k, g).
  • Glottal: closure at the vocal folds, producing a glottal stop (often written ʔ); involves the throat.
  • Other places occur cross-linguistically (labio-dental, uvular, etc.), often involving the tongue for oral closures.

Voicing, aspiration, and timing

Stops may be voiced or voiceless depending on whether the vocal folds vibrate during the closure. Many languages contrast voiced and voiceless pairs (for example, English b/d/g versus p/t/k). Other contrasts involve aspiration (a puff of air on release) or glottalization. Phoneticians often measure voice onset time (the timing between release and vocal fold vibration) to describe such differences.

Distribution and examples

Different languages show different inventories of stops and different patterns of use. English uses bilabial, alveolar, and velar stops regularly; some languages add uvular or retroflex stops. Stops can occur at the beginning, middle, or end of syllables and interact with surrounding vowels and consonants to affect syllable structure and timing. In orthographies, stops are typically represented by letters such as p, t, k, b, d, g, though the spelling-to-sound relationship varies.

Terminology can vary: "stop," "plosive," and "occlusive" are used in slightly different senses. "Plosive" emphasizes the burst of air at release. Affricates combine a stop-like closure with a fricative-like release. Nasals (like m, n) are also occlusive but allow airflow through the nose rather than the mouth, so they are not classified as stops in the narrow sense used by many phonologists. Because of their clear articulatory gesture and acoustic salience, stops play a central role in phonological descriptions and language learning.

For further reading on articulatory details, acoustic properties, and cross-linguistic inventories, consult introductory texts in phonetics and language-specific descriptions (consonant inventories and phonetics resources).