Here I think that it's important to distinguish between language (a specific system of discrete symbols, organised in a recursive way) from communication (ability to send information from one animal to another). Plenty, plenty animals show non-linguistic communication; including humans. But language itself pretty much exclusive to humans.
What those elephants are showing is one of the requirements for language, the ability to assign discrete and arbitrary symbols to things around them. However it's also missing another key element - the ability to combine those symbols recursively, like they were building blocks of something bigger.
It might be also worth to redo a few intelligence tests with them. If Chomsky is to be taken seriously in this regard (I have my doubts), the primary role of language wouldn't be communication, but to structure and formalise your thoughts; now that we know that they assign symbols to things, perhaps we should be looking on how they handle them.
Of course, it's a bit of a petty detail. And is equally valid both ways.
But really goes to show how humanity has got so much wrong. We again and again discover animals doing things we have classed as uniquely human.
In every way, we decide humans are unique amongst animal spices. Seems to fail if we wait long enough.
And before any vegans use this to make some argument. Your choices are yours. But I am yet to see any other animal spices shame members for the diet they evolved eating. So maybe that will be the unique way to measure humanity that lasts. Because eating meat. Or even treating it with cruelty, ain't one. if you doubt it, look at the insects that breed inside living animals. Many imprisoning the creature as their children grow, then eat it alive.
As much as I'd rather humanity be caring. This is not your argument against meat eaters.