Nasalization

[ney-zuh-lahyz]

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. An archetypal nasal sound is [n].

In the International Phonetic Alphabet nasalization is indicated by printing a tilde 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, are more legible in most fonts than .

Nasal vowels

Nasal vowels are found in many languages, and in a large subset, such as French, Portuguese, Breton, Polish, as well as in several other language families outside Europe, they contrast with oral vowels. Many languages, however, only have oral vowels; this is the case, among others, of English — with the possible exception of the Texas "twang".

There are occasional cases where vowels show contrasting degrees of nasality.

Nasalized consonants

By far the most common nasalized sounds are nasal stops such as [m], [n] or [ŋ]. They may be called stops because airflow through the mouth is blocked, though air flows freely through the nose. Their non-nasal articulatory counterparts are the oral stops. In theory, these nasal consonants could therefore perfectly be represented as, respectively, [b̃], [d̃] or [g̃]. The reason why these nasal consonants have their own symbol is their frequency in the world's languages.

Nasalized versions of other consonant sounds also exist, though they are much rarer than either nasal stops or nasal vowels. Some of the South Arabic languages have phonemic nasalized fricatives, such as [z̃], 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 [ʝ̃]. 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 [ȷ̃] in other Athabaskan languages. In Umbundu, phonemic /ṽ/ contrasts with (allophonically) nasalized [w̃], and so is likely to be a true fricative rather than an approximant.

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 Extensions to the IPA: [n͋] is an alveolar nareal fricative, with no airflow out of the mouth, while [v͋] is an oral fricative (a [v]) with simultaneous nareal frication. No known natural language makes use of nareal consonants.

Denasalization

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.