I can't wait for all the research papers from the "They Can Talk" talking buttons studies. Absolutely fascinating stuff coming out - pets apparently learn to understand not only simple words, but complex constructions and grammar, when sufficiently modeled by their people. They even chain together words in meaningful ways to augment their vocabulary and communicate complex ideas.

Simple vocalizations are cool, but that's pretty limited communication, and if they're capable of so much more, it's pretty likely that they're using individual meows in much the same way a human would under the same constraints. Imagine only being able to say "HEY!" and having to use context and body language in every situation.

TheyCanTalk have got n>10k animals so far, mostly cats and dogs, with a handful of pigs, rabbits, goats, and others. I've seen a few horses, cows, and others on social media, too, and they've got a lot more customers than study participants.