Occlusive

In phonetics, an occlusive, sometimes known as a stop, is a consonant sound produced by blocking (occluding) airflow in the vocal tract, but not necessarily in the nasal tract. The duration of the block is the occlusion of the consonant. An occlusive may refer to one or more of the following, depending on the author:

Oral occlusive may mean any of the above apart from nasal occlusives, but typically means stop/plosive. Nasal occlusive may be used to distinguish the simple nasal sounds from other nasal consonants.

The terms 'stop' and 'occlusive' are used inconsistently in the literature. They may be synonyms, or they may distinguish nasality as here. However, some authors use them in the opposite sense to here, with 'stop' being the generic term (oral stop, nasal stop), and 'occlusive' being restricted to oral consonants. Ladefoged and Maddieson (1996) prefer to distinguish 'stop' from 'nasal'. They say,

All languages in the world have occlusives and most have at least the voiceless stops [p], [t], [k] and the nasals [n], and [m]. However, there are exceptions.

Colloquial Samoan lacks the coronals [t] and [n], and several North American languages, such as the northern Iroquoian languages, lack the labials [p] and [m]. In fact, the labial plosive is the least stable of the voiceless stops in the languages of the world, as the unconditioned sound change [p] → [f] (→ [h] → Ø) is quite common in unrelated languages, having occurred in the history of Classical Japanese, Classical Arabic and Proto-Celtic, for instance.

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