I would argue this a little (while conceding their indiginous languages don’t top 100 words). Great ape sign language experiments have been routinely successful in giving the apes 150+ word vocabularies. Why would they have the capability for this in the lab if they’re not using it in the wild? In Roger Fout’s book Next of Kin he makes the point that chimpanzees in the wild exhibit a limited vocabulary including invitations to groom, mate, and even such phrases as “may I pass?” (in body “language” and gesture). One thing I remember from the book was when Washoe, who had been raised to use ASL in Nevada, was sent to the University of Oklahoma and thrown in with chimps who had no knowledge of sign language. When she hit her estrus and wanted to mate, she used the ASL sign “hug” and apparently the male chimps learned that sign very quickly. I seem to recall that the other female chimps communicated their invitations differently but I don’t have the book with me now.