The Na'vi categorize their social songs into two groups that are analogous to terrestrial dance tunes and banquet songs. The dance tunes are lively, upbeat, and extremely rhythmic. They are sung in unison, either while dancing or observing the dance. They are accompanied by drums. The category of banquet songs comprises three distinct types of songs: origin songs, historical epics of the Na’vi, and praise songs. These are the most musically complex songs; women sing a heterophonic melody while men maintain a drone that the Na'vi believe represents the spirit of Eywa.
The Na'vi dance tunes, which are sung in unison by clan members, are all very similar in character. The majority of these songs are in a duple meter (two or four beats to a bar). Any kind of drum will provide a suitable accompaniment, but Log Drums, Pole Drums, small Gourd Drums, and Tree Drums are the instruments most commonly used to accompany dance. It is also common for the Na'vi to use whizzers and small one-pitched whistles, blown for emphasis during a dance. Because the Na'vi sing these songs while dancing, maintaining the rhythm of the lyrics is considered far more important that accurately singing the melody. In the liveliest dances, the “singing” is reduced to highly rhythmic and exuberant chanting or shouting.
Na'vi banquet songs include origin songs which are lengthy (up to four hours) re-tellings of Pandoran mythology such as the legend of the Toruk Makto. Historical epics recount great battles and great hunts, while praise songs are sung for the most heroic Na’vi leaders and warriors. Youngsters learn the majority of their history by listening to their elders sings these epics.
To outsiders, all of the banquet songs may sound remarkably similar musically. However, each song structure is distinguished by the style of its prose, line length and number of lines, and the rhyme scheme.
Origins songs use a rhyme scheme of AAA BB AAA CC AAA, etc. They are sung in a very old, very formal style of Na'vi language. Each line with an A rhyme is fourteen syllables long. Lines which use other rhymes are either seven or twelve syllables long. No new origin songs have been written during living memory.
Historical epics use a rhyme scheme of paired phrases (AA BB, CC, etc.). All lines are twelve syllables long. A simpler language style is utilized, presumably so that the meaning is not lost on later generations. This also simplifies learning for Na’vi children. New historical songs are composed when an event warrants a place in clan lore, but since there is no concept of “song composer” in Na'vi culture, anyone with a gift for singing, rhyming and remembering may compose a historical song.
Praise songs are simpler still. There is no set structure apart from a rhyme scheme of ABAB CDCD, etc. Lines may be any number of syllables long.
Since these songs are the primary means by which Na’vi trace their history and genealogy, precise diction and accurate repetition are considered of utmost importance. Although all Na’vi are expected to memorize these historical tales and be able to sing them, those with the best memories and most accurate voices are entrusted with the responsibility of preserving these songs and passing them down to the next generation.
Musically, banquet songs are the most complex and impressive of Na'vi songs. The musical texture is divided between men and women: women sing the melody and lyrics in their typical heterophonic fashion (in which various performers sing slightly different melodies) while men provide what serves as a drone. The melody can be performed in one of two ways: either one woman will sing a fairly unadorned version or, more commonly, many women will sing in their typical cascading heterophonic style but with much ornamentation, almost in a competitive manner. Solo renditions are heard from time to time, but the Na'vi prefer them sung with great gusto by a large group.
As for the men’s drone, rather than holding a steady pitch each man independently fluctuates his pitch microtonally, varying up to one and three-fifths pamtseo ‘it (or “musical small bits”) on either side of the fundamental pitch. The result gives an overall impression of a drone, but it exhibits a “living” quality in the subtle movements among the men’s voices. The Na’vi believe that this “living” drone represents the spirit of Eywa, much akin to the ancient Greek concept of the music of the spheres.
Pandorapedia - Social Songs article