Yoik, Joik, Luohti, Vuolle or juoiggus is a traditional Sami form of song.

Originally, yoik referred to only one of several Sami singing styles, but in English the word is often used to refer to all types of traditional Sami singing. Its sound is comparable to the traditional chanting of some Native American cultures.

Each yoik is meant to reflect a person or place. This does not mean that it is a song about the person or place, but that the yoiker is attempting to transfer "the essence" of that person or place into song - one yoiks their friend, not about their friend. It usually has short lyrics or no lyrics at all. This type of song can be deeply personal or spiritual in nature. Improvisation is not unusual. However, there are other forms of yoik (in the expanded sense of the word) that have a more epic type of lyrics.

In northern Sami areas, most yoiks are personal, that is, tied to a specific person. A yoik is often made for a person at the time they are born (Wikipedia).

The Sami Yoik by Kathryn Burke

The yoik, a unique form of cultural expression for the Sami people, can be understood as a metaphor for Sami traditional culture itself. Like the Sami people, the yoik has been misunderstood, ridiculed, appropriated, and even threatened. A form of song which utilizes a scale and vocalizations which are unfamiliar to virtually everyone in the Western (American and European) world, the history of the yoik is representative of all the encroachment and abuse that the Sami people have suffered at the hands of outsiders.

http://www.utexas.edu/courses/sami/diehtu/giella/music/yoiksunna.htm