Inphonetics, anocclusive, sometimes known as astop, is aconsonant soundproduced by occluding (i.e. blocking) airflow in thevocal tract, but not necessarily in thenasal tract. The duration of the block is theocclusion 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 othernasal 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[2] and most have at least the voiceless stops[p],[t],[k] and the nasals[n], and[m]. However, there are exceptions.
ColloquialSamoan lacks thecoronals[t] and[n], and several North American languages, such as the northernIroquoian languages, lack thelabials[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 ofClassical Japanese,Classical Arabic andProto-Celtic, for instance.
Some of theChimakuan,Salishan, andWakashan languages nearPuget Sound lacknasal occlusives[m] and[n], as does theRotokas language ofPapua New Guinea. In some African and South American languages, nasal occlusives occur only in the environment ofnasal vowels and so arenot distinctive.
FormalSamoan has nasals/nŋ/ and/t/ but only one word withvelar[k]; colloquial Samoanconflates these to/ŋk/.NiʻihauHawaiian has[t] for/k/ to a greater extent than Standard Hawaiian, but neither distinguishes a/k/ from a/t/. It may be more accurate to say that Hawaiian and colloquial Samoan do not distinguish velar and coronal stops than to say they lack one or the other.
Yanyuwa distinguishes nasals and plosives in seven places of articulations /m n̪ n ṉ ɳ ŋ̟ ŋ̠/ and /b d̪ d ḏ ɖ ɡ̟ ɡ̠/ (it does not have voiceless plosives) which is the most out of all languages.[3]