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|Sound change and alternation|
In phonetics, nasalization (or nasalisation) is the production of a sound while the velum is lowered, so that some air escapes through the nose during the production of the sound by the mouth. An archetypal nasal sound is [n].
In the International Phonetic Alphabet, nasalization is indicated by printing a tilde diacritic U+0303 ◌̃ combining tilde (HTML
̃) above the symbol for the sound to be nasalized: [ã] is the nasalized equivalent of [a], and [ṽ] is the nasalized equivalent of [v]. An older IPA subscript diacritic [ą], called an ogonek, is still seen, especially when the vowel bears tone marks that would interfere with the superscript tilde. For example, [ą̄ ą́ ą̀ ą̂ ą̌] are more legible in most fonts than [ã̄ ã́ ã̀ ã̂ ã̌].
Nasal vowels are found in some European languages, such as French, Portuguese, Breton, and Polish. In these and some non-European languages, nasal vowels contrast with oral vowels. Many languages, however, only have oral vowels.
There are occasional cases where vowels show contrasting degrees of nasality.
By far the most common nasal sounds are nasal consonants such as [m], [n] or [ŋ]. Most nasal consonants are occlusives, where airflow through the mouth is blocked and redirected through the nose. Their oral counterparts are the stops.
Other nasal(ized) consonants
Nasalized versions of other consonant sounds also exist, though they are much rarer than either nasal occlusives or nasal vowels. Some South Arabian languages use phonemic nasalized fricatives, such as /z̃/, which sounds something like a simultaneous [n] and [z]. The sound written ⟨r⟩ in Chinese has an odd history; for example, it has been borrowed into Japanese as both [z] and [n]. It seems likely that it was once a nasalized fricative, perhaps a palatal [ʝ̃]. In Coatzospan Mixtec, fricatives and affricates are nasalized before nasal vowels, even when they are voiceless. In the Hupa velar nasal /ŋ/, the tongue often does not make full contact, resulting in a nasalized approximant, [ɰ̃]. This is cognate with a nasalized palatal approximant [ȷ̃] in other Athabaskan languages. In Umbundu, phonemic /ṽ/ contrasts with the (allophonically) nasalized approximant [w̃], and so is likely to be a true fricative rather than an approximant.[further explanation needed] In Old and Middle Irish, the lenited ⟨m⟩ was a nasalized bilabial fricative. Sundanese has an allophonic nasalized glottal stop [ʔ̃]; nasalized stops can only occur with pharyngeal articulation or lower, otherwise they would be simple nasals. Nasal flaps are common allophonically. Many West African languages have a nasal flap [ɾ̃] (or [n̆]) as an allophone of /ɾ/ before a nasal vowel; Pashto, however, has a phonemic nasal retroflex lateral flap. Other languages, such as the Khoisan languages of Khoekhoe and Gǀui, as well as several of the !Kung languages, include nasal click consonants. Nasalization of these phonemes is denoted with a superscript ⟨ᵑ⟩ preceding the consonant (for example, ⟨ᵑǂ⟩). Nasalized laterals such as [l̃] are easy to produce, but rare to non-existent as phonemes; often when [l] is nasalized it becomes [n].
Besides nasalized oral fricatives, there are true nasal fricatives, called nareal fricatives, sometimes produced by people with disordered speech. In these sounds, the turbulence in the airflow characteristic of fricatives is produced not in the mouth but in the nasal cavity. A tilde plus trema diacritic (two dots representing the nostrils) is used for this in the extensions to the IPA: [n͋] is a voiced alveolar nareal fricative, with no airflow out of the mouth, and [n̥͋] is the voiceless equivalent, whereas [v͋] is an oral fricative with simultaneous nareal frication. No known language makes use of nareal consonants in non-disordered speech.
Nasalization may be lost over time. There are also denasal sounds, which sound like nasals spoken with a head cold. They may be found in non-pathological speech as a language loses nasal consonants, as in Korean.
Vowels assimilate to surrounding nasal consonants in many languages, such as Thai, creating nasal vowel allophones. Some languages exhibit a nasalization of segments adjacent to phonemic or allophonic nasal vowels, such as Apurinã. Contextual nasalization can lead to the addition of nasal vowel phonemes to a language. This happened in French, where most final consonants disappeared, but where in the case of final nasals, the preceding vowels became nasal, introducing a new distinction into the language. An example where this happened is vin blanc [vɛ̃ blɑ̃] ('white wine'), ultimately from Latin vinum and blancum.
- Nasal consonant
- Prenasalized consonant
- Nasal release
- Eclipsis, a similar process in Gaelic that is often called "nasalization"
- Thurneysen, Rudolf; D. A. Binchy, Osborn Bergin (trans.) (1946). A Grammar of Old Irish. Dublin: Dublin Institute for Advanced Studies. p. 85. ISBN 1-85500-161-6.
- Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. p. 134. ISBN 0-631-19814-8.
- Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. p. 268. ISBN 0-631-19814-8.
- The World Atlas of Language Structures Online – Chapter 10 – Vowel Nasalization