I have friends in Sapmi (Lappland), sadly not singers. But their aunt Berit Nordland produced a wonderful CD of joik back in the 80s, which I have- sadly it seems impossible to get now.
You don't sing a joik- you joik a person, animal, place, weather etc. A person's joik is a very private thing- it's the height of bad manners to misuse it, e.g. to sing it in public without (at least tacit) permission. The songs consist largely of mouth music- the "I'll oil loyal lawyer's alloy loy" bits- but the few words can be very pithy. One joik my friends told me about simply said "Per who sits on the shingle". His wife had drowned in the river; for the rest of his life, he would spend hours near the spot, grieving.