Occlusive

For occlusives in cosmetics, seeMoisturizer.For other uses, seeOcclusion.

Inphonetics,anocclusive,sometimes known as astop,is aconsonantsoundproducedby occluding (i.e. blocking) airflow in thevocal tract,but not necessarily in thenasal tract.The duration of the block is theocclusionof the consonant. An occlusive may refer to one or more of the following, depending on the author:

• Stops,or more precisely,oral stops—also known asplosives—are oral occlusives, where the occlusion of the vocal tract stops all airflow—oral and nasal.

Examples in English are (voiced)/b/,/d/,/ɡ/and (voiceless)/p/,/t/,/k/.

• Nasals,also known asnasal stops,are nasal occlusives, where occlusion of the vocal tract shifts the airflow to the nasal tract.

Examples in English are/m/,/n/,and/ŋ/.

• Affricatessuch as English/tʃ/,/dʒ/are partial occlusives. Typicallystopsandaffricatesare contrasted, but affricates are also described asstops with fricative release,contrasting withsimple stops(= plosives).
• Implosives,in which theairstreamdiffers from typical stops and affricates (no examples in English).
• Ejectives,with yet another airstream (no examples in English).
• Click consonants,such as the exclamationtsk! tsk!made when expressing reproach (often humorously) orpity,are double occlusives with yet a fourth airstream mechanism. They may be oral occlusives,nasals,affricates,orejective.

Oral occlusivemay mean any of the above apart from nasal occlusives, but typically means stop/plosive.Nasal occlusivemay 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,

Note that what we call simply nasals are called nasal stops by some linguists. We avoid this phrase, preferring to reserve the term 'stop' for sounds in which there is a complete interruption of airflow.

Common occlusives

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

ColloquialSamoanlacks thecoronals[t]and[n],and several North American languages, such as the northernIroquoianlanguages, 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 ArabicandProto-Celtic,for instance.

Some of theChimakuan,Salishan,andWakashanlanguages nearPuget Soundlacknasal occlusives[m]and[n],as does theRotokas languageofPapua New Guinea.In some African and South American languages, nasal occlusives occur only in the environment ofnasal vowelsand so arenot distinctive.

FormalSamoanhas nasals/nŋ/and/t/but only one word withvelar[k];colloquial Samoanconflatesthese to/ŋk/.Ni‘ihauHawaiianhas[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.

Yanyuwadistinguishes 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.