Implosive consonant

Implosive consonants are stops (and possibly affricates) with a mixed glottalic ingressive and pulmonic egressive airstream mechanism. That is, the airstream is controlled by moving the glottis downward in addition to expelling air from the lungs. Therefore, unlike the purely glottalic ejective consonants, implosives can be modified by phonation. Contrastive implosives are found in approximately 13% of the world's languages.

In the International Phonetic Alphabet, implosives are indicated by modifying the top of a letter (voiced stop) with a downward-facing hook: ⟨ɓ ɗ ʄ ɠ ʛ ⟩.

Articulation

During the occlusion of the stop, pulling the glottis downward rarefies the air in the vocal tract. The stop is then released. In languages where implosives are particularly salient, this may result in air rushing into the mouth, before flowing out again with the next vowel. To intake air sharply this way is to "implode" a sound.

However, probably more typically there is no movement of air at all, contrasting with the burst of the pulmonary plosives. This is the case with many of the Kru languages, for example. Note that this means implosives are phonetically sonorants (i.e. not obstruents) as the concept of sonorant is usually defined. However, phonologically implosives can pattern as both; that is, they may be phonological sonorants or obstruents depending on the language. Clements (2002) actually proposes that implosives are phonologically neither obstruents nor sonorants, and that they need to be described by the features −obstruent and −sonorant.