Pets are able to pick up on human language, and can understand dozens of words in whatever language is the default for the house. For the people willing to spend the time and effort to use buttons that make words back, there's a few instances of dogs and cats both learning a pretty substantial vocabulary and communicating things like likes and dislikes, wants and needs, to their humans using buttons that make the words. Lots of videos online of people with genuine success.

My favorite instance was someone who had the word "litterbox" as a button. When the cat asked for a treat and was denied, it went over, stared at the human, and hit "litterbox." As a genuine "fuck you" because it was the only "bad" word it had. Cats, and not dogs, apparently also understand that when it's raining, humans can't do anything about it. Dogs, apparently, not quite as quick-witted.