Ainu religion has no scripture and no priesthood. What it has instead is a body of chanted oral literature, and the language is inseparable from it. The kamuy yukar, the songs of the kamuy, are narrated in the first person by the kamuy itself: the bear, the owl, the fox or the fire tells the audience what happened to it and what it thought about the humans it met. The effect is not decorative. It is the theological content of the form. A kamuy is a person with a point of view, and the grammar of the song obliges the audience to occupy it.
Each song carries a refrain, a fixed burden repeated at intervals through the narrative, which identifies the song and marks its rhythm as the chanter beats time. The refrains are often untranslatable, and collectors have generally left them as sound.
The literature was recorded late and largely by outsiders. Missionary and ethnographic collectors compiled dictionaries, grammars and texts from the late nineteenth century onward, and the material they left is the main documentary basis for what is known. One collection stands apart because it was made from inside: a young Ainu woman transcribed the kamuy yukar she had learned from her grandmother, in Latin letters, and translated them into Japanese herself, and the volume appeared in 1923.
Because the religious register lives in this literature and not in a text of rules, the loss of the language and the loss of the tradition are the same loss, which is why revival work centres on the songs.