The evidence discussed for animals using language in that language log posting is most unconvincing, I agree.

I'm not sure how I'd define language, but one thing I think I'd consider can only happen with language is communicating a description of a novel change in the environment.

The primary evidence I was thinking came from an anecdote in a biological anthropology lecture, and relates to vervet monkeys in the wild - unfortunately I couldn't find a reference to it with a quick google search, but the assertion was that vervet monkeys make up new warning calls for new potential predators by combining existing calls. Probably the reason that I couldn't find a reference to this is that it was anecdotal and controversial, of course. Indeed, the only agreement that I can find is that vervets have distinct warning calls for "leopard", "snake" and eagle, and it's hard to see how a combination of these calls could be descriptive, rather than just the monkey being unsure which warning call to use.

Perhaps I'd be on stronger ground if I hadn't included the word "plenty". On searching around a bit more, there seems to be plenty of debate on the subject, and very little consensus.

Interesting points, though, thanks. I wish I had more time to investigate the subject properly...