"Vicuña" doesn't translate, it retains the Spanish spelling and pronunciation in English. The closest thing most Americans are familiar with to a vicuña is a llama--a vicuña is basically a more delicate form of the llama, and the wool is much finer and more valuable (although I do not believe it is legal to harvest this wool.) Under the Inca empire only the Inca (emperor) could have articles made of vicuña wool, if anybody else was found with it they were put to death.
thanks, I taked a lot of pictures of vicuñas, llamas and alpacas (more little than llama) in my trip to Perú. The most difficult to take a picture it's the guanaco (danger of exctintion in nowadays, I don't see no one)