Elephants and whales both use "personal individual identifiers" in their messages... we would call such a 'name'.
Cool. Interesting, but not language.
Also IIRC we have seen one of lab animals teaching its own child the sign language it had learned from humans, but I forget the reference.
I've also seen that. I've also seen critques of the whole field. In my opinion (q.v. Stephen Pinkers' [i]The Language Instinct[i]) claims of sign language in chimps have been grossly exagurated and rely heavily on generous levels of interpretation by the experimenters. Although one case of Orang Utan language learning still stands above other examples.
In any case no animal language learning has approached even the linguistic capabilities of an intelligent two year old and certainly has never approached that of a typical adult.
I don't accept that I'm afraid. One strand on the Neanderthal debate is the suggestion that they might have communicated by whistles; this would tie into the 'co-existant but apparently in mutual ignorance' scenario discussed on another thread.
I'm not sure I understand the relevance of your point? Of course ancestral, and 'branch', homonids will have possessed some kind of intermediary between human language and ape communication.
Language is IMO a communications protocol; it is a technology, and tool as much as an axe is a tool. The qualitative complexity of our protocol does not make it meaningfully unique, even if it is the most developed such protocol on the planet.
I'm unsure as to what you mean by 'meaningfully unique'? Meaningful in what sense?