Joik - WikipediaThis type of song can be deeply personal or spiritual in nature, often dedicated to a human being, an animal, or a landscape as a personal signature. Improvisation is not unusual. Each joik is meant to reflect a person or place. The Sami verb for presenting a joik (e.g. Northern Sami juoigat) is a transitive verb, which is often interpreted as indicating that a joik is not a song about the person or place, but that the joiker is attempting to evoke or depict that person or place through song – one joiks one's friend, not about one's friend (similarly to how one doesn't paint or depict about a flower, but depicts the flower itself)
Well, I am not so sure about that. The sentence may be a bit ambiguous, and I think your interpretation is possible. But "nerve" can also mean "core, essence", and I would rather read this as something like "a form of art that can capture the essence of a person".
Joik is a form of singing that is used to describe a person (or an animal or landscape). This description is not done with words; the singer uses the melody and rhythm to characterize or embody the person. As Wikipedia describes it:
Joik - Wikipedia
On this background, I understand "menneske" in your text as the person who is depicted, not the person who listens to the joik. Do you have more context that could make the meaning clearer?