Sean Nós
Sean nós is a highly-ornamented style of solo, unaccompanied singing in the Irish tradition. Sean nós literally means old style, therefore it is incorrect to say "the sean nós style", but more correct simply to refer to something as sean nós.
Though sean nós songs can be relatively simple in structure, some are long, highly stylised and melodically complex, and good performance typically involves substantial ornamental and rhythmic variation from verse to verse.
A number of songs, especially older ones, can be modal as opposed to diatonic in melody, presenting problems for singers unaccustomed to the 'layout' of modal scales. Some melodies properly incorporate slightly larger or smaller intervals than the western standard, but it is rare to hear them performed properly in the 21st century.
Sean nós can be applied to songs in English or Irish, as it is the method of singing which is distinctive and not the lyrics, but some purists still insist that songs in the English language cannot be regarded as belonging to the tradition.
Styles vary around Ireland, generally conforming quite closely to the different dialects of Irish in different regions of Ireland, from the relatively unadorned and nasal style of the north to the more decorated and lyrically distinct styles of the south and west. The Waterford Gaeltacht of An Rinn has its own style too, in spite of its small size. With the advent of recording media and ease of travel and interaction with other singers, however, these lines of distinction are becoming less definite and some singers are known to adopt different styles for songs from the different parts of the country.
New composition is a controversial issue within sean nós singing, with some singers insisting that the tradition needs new material but others saying that only older, "purer" songs deserve a place in the extensive corpus of sean nós songs.
The tradition was for years exclusively oral, but songs started to be written down in the eighteenth century and were distributed in print from then on, with a few songs known to have been committed to script even earlier. A song-book for Elizabeth I contained English interpretations of sean nós songs.
Apart from stylistic decoration, which itself varies from region to region, other features of sean nós singing include nasalisation, especially in Ulster, a more specific nasalisation towards the end of a phrase in the south, leading to the addition of an "n" or "ng" sound at the end of words, "slides" or glissandi, especially when sung by women, glottal stops, extreme breath control leading to almost impossibly long extended phrases, and for some songs recitation of the last line as opposed to singing.
Most songs are non-gender specific but there are a few that men tend not to sing, though women do not seem to have the same compunction. Modern performance often places songs out of context, which is a new departure for sean nós singing, but most songs are lullabies, laments, narratives, love songs or devotional songs. Some can be highly comedic.
A large number of sean nós songs are macaronic: that is to say they combine two or more languages - usually Irish and English but occasionally Irish and French and other European languages, including Latin.