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. In the International Phonetic Alphabet, nasalization is indicated by printing a tilde diacritic above the symbol for the sound to be nasalized: is the nasalized equivalent of, and is the nasalized equivalent of. A subscript diacritic, called an ogonek or nosinė, is sometimes seen, especially when the vowel bears tone marks that would interfere with the superscript tilde. For example, are more legible in most fonts than.
By far the most common nasal sounds are nasal consonants such as, or. Most nasal consonants are occlusives, and airflow through the mouth is blocked and redirected through the nose. Their oral counterparts are the stops.
Nasalized consonants
Nasalized versions of other consonant sounds also exist but are much rarer than either nasal occlusives or nasal vowels. Some South Arabian languages use phonemic nasalized fricatives, such as, which sounds something like a simultaneous and. The Middle Chinese consonant has an odd history; for example, it has evolved into and in Standard Chinese; / and in Hokkien; / and / while borrowed into Japan. It seems likely that it was once a nasalized fricative, perhaps a palatal. In Coatzospan Mixtec, fricatives and affricates are nasalized before nasal vowels even when they are voiceless. In the Hupa, the velar nasal often has the tongue not make full contact, resulting in a nasalized approximant,. That is cognate with a nasalized palatal approximant in other Athabaskan languages. In Umbundu, phonemic contrasts with the nasalized approximant and so is likely to be a true fricative rather than an approximant. In Old and Middle Irish, the lenited was a nasalized bilabial fricative. Sundanese has an allophonic nasalized glottal stop ; nasalized stops can occur only with pharyngeal articulation or lower, or they would be simple nasals. Nasal flaps are common allophonically. Many West African languages have a nasal flap as an allophone of 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 the phonemes is denoted with a superscript preceding the consonant. Nasalized laterals such as are easy to produce but rare or nonexistent as phonemes; often when is nasalized, it becomes.
True nasal fricatives
Besides nasalized oral fricatives, there are true nasal fricatives, previously called nareal fricatives. They are sometimes produced by people with disordered speech. The turbulence in the airflow characteristic of fricatives is produced not in the mouth but in the nasal cavity. A superimposed homothetic sign that resembles a colondivided by a tilde is used for this in the extensions to the IPA: is a voiced alveolar nasal fricative, with no airflow out of the mouth, and is the voiceless equivalent; is an oral fricative with simultaneous nasal frication. No known language makes use of nasal fricatives in non-disordered speech.
Denasalization
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.
Contextual nasalization
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. That happened in French, most of whose final consonants disappeared, but its final nasals made the preceding vowels become nasal, which introduced a new distinction into the language. An example is vin blanc , ultimately from Latinvinum and blancum.
