|
In phonetics, a nasal, also called a nasal occlusive, nasal stop in contrast with a nasal fricative, or nasal continuant, is an occlusive consonant produced with a lowered velum, allowing air to escape freely through the nose. Examples of nasals in English are and , in words such as ''nose'' and ''mouth''. Nasal occlusives are nearly universal in human languages. There are also other kinds of nasal consonants in some languages. == Definition == Nearly all nasal consonants are nasal occlusives, in which air escapes through the nose but not through the mouth, as it is blocked (occluded) by the lips or tongue. The oral cavity still acts as a resonance chamber for the sound. Rarely, non-occlusive consonants may be nasalized. Most nasals are voiced, and in fact, the nasal sounds and are among the most common sounds cross-linguistically. Voiceless nasals occur in a few languages such as Burmese, Welsh, Icelandic and Guaraní. (Compare oral stops, which block off the air completely, and fricatives, which obstruct the air with a narrow channel. Both stops and fricatives are more commonly voiceless than voiced, and are known as obstruents.) In terms of acoustics, nasals are sonorants, which means that they do not significantly restrict the escape of air (as it can freely escape out the nose). However, nasals are also obstruents in their articulation because the flow of air through the mouth is blocked. This duality, a sonorant airflow through the nose along with an obstruction in the mouth, means that nasal occlusives behave both like sonorants and like obstruents. For example, nasals tend to pattern with other sonorants such as and , but in many languages, they may develop from or into stops. Acoustically, nasals have bands of energy at around 200 and 2,000 Hz. 1. The symbol is commonly used to represent the dental nasal as well, rather than , as it is rarely distinguished from the alveolar nasal. Examples of languages containing nasal occlusives: The voiced retroflex nasal is is a common sound in Languages of India. The voiced palatal nasal is a common sound in European languages, such as: Spanish , French and Italian , Catalan and Hungarian , Czech and Slovak , Polish , Occitan and Portuguese , Serbo-Croatian , and (before a vowel) Modern Greek . Many Germanic languages, including German, Dutch, English and Swedish, as well as varieties of Chinese such as Mandarin and Cantonese, have , and . Tamil has a six-fold distinction between , , , , and (ம,ந,ன,ண,ஞ,ங). Catalan, Occitan, Spanish, and Italian have , , as phonemes, and and as allophones. Nevertheless, in several American dialects of Spanish, there is no palatal nasal but only a palatalized nasal, , as in English ''canyon''. In Brazilian Portuguese and Angolan Portuguese , written , is typically pronounced as , a nasal palatal approximant, a nasal glide (in Polish, this feature is also possible as an allophone). Semivowels in Portuguese often nasalize before and always after nasal vowels, resulting in and []. What would be coda nasal occlusives in other West Iberian languages is only slightly pronounced before dental consonants. Outside this environment the nasality is spread over the vowel or become a nasal diphthong (''mambembe'' , outside the final, only in Brazil, and ''mantém'' in all Portuguese dialects). The term 'nasal occlusive' (or 'nasal stop') is generally abbreviated to ''nasal''. However, there are also nasalized fricatives, nasalized flaps, nasal glides, and nasal vowels, as in French, Portuguese, and Polish. In the IPA, nasal vowels and nasalized consonants are indicated by placing a tilde (~) over the vowel or consonant in question: French ''sang'' , Portuguese ''bom'' . 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nasal consonant」の詳細全文を読む スポンサード リンク
|