Urtin duu, or “long song”, is a traditional singing style in Mongolia. This type of song is characterized by having minimal lyrics (anything from one sentence to a handful of sentences) that are stretched out over many measures of music. Long song can be sung a capella or accompanied by an instrument. (In the video below, the accompaniment is of the morin khuur, or horse head fiddle.) What instrument played in accompaniment depends on ethnic group or region. For more details on musical style, I found this article on Wikipedia helpful (Long song).
The singer in the video above is Namjilyn Norovbanzad (1931-2002). She was recognized as the “People’s Artist” in 1969 and voted “Singer of the Century” in 2000. One could easily argue that she was a national treasure and highly gifted in this vocal style.