In
phonetics, 'nasalization' 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. The effect is as if an [n] sound were produced simultaneously with the oral sound.
In the
International Phonetic Alphabet nasalization is indicated by printing a
tilde above the symbol for the sound to be nasalized: is the nasalized equivalent of , and is the nasalized equivalent of . An older IPA subscript diacritic [Ä…], called an
ogonek, is still seen, especially when the vowel bears
tone marks that would interfer with the superscript tilde. , for example, is more legible in most fonts than .
Nasal vowels
Main articles: Nasal vowel
The most common nasalized sounds are nasal vowels, found in
French,
Polish,
Portuguese, and the
Texas "twang". There are occasional cases where vowels show contrasting degrees of nasality.
Nasalized consonants
However, there are also nasalized consonants which contrast with purely oral consonants. Some of the
South Arabic languages have nasalized fricatives, such as , which sounds something like a simultaneous [n] and [z]. The sound written ''r'' in
Mandarin 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 . In the
Hupa velar nasal , the tongue often does not make full contact, resulting in a nasalized approximant, . This is
cognate with a nasalized in other
Athabaskan languages. In
Umbundu, phonemic contrasts with (
allophonically) nasalized , and so is likely to be a true fricative rather than an approximant.
Phonologically speaking, nothing prevents from describing
nasal stops such as , or as the nasalized counterpart of voiced oral stops. In theory, these nasal consonants could therefore perfectly be represented as, respectively, , or . The only reason why these nasal consonants have their own symbol is their frequency in the world's languages – in contrast, for example, with the nasal(ized) constrictives (e.g., ).
Nasal stops are called stops because airflow through the mouth is blocked, but air flows freely through the nose.
Nareal consonants
Besides nasalized oral fricatives, there are true nasal fricatives, called ''nareal fricatives,'' sometimes produced by people with speech defects. That is, the turbulence in the airflow characteristic of fricatives is produced not in the mouth but in the nasal passages. A tilde plus
trema diacritic is used for this in the
Extended IPA: is an alveolar nareal fricative, with no airflow out of the mouth, while is an oral fricative (a [v]) with simultaneous nareal frication. No known natural language makes use of nareal consonants.
Denasalization
Main articles: Denasal
Nasalization may be lost over time. There are also
denasal sounds, which sound like nasals spoken with a head cold, but these are not used in non-pathological speech.
See also
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Nasal consonant
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Prenasalized stop
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Nasal release