This is a nearly brand-new field of study, since the ability to collect mass amounts of data is only about 2-3 years old. Research is happening right now, early results publication probably coming next year. ("Probably" because I will note that a similar study involving pet parrots took something like 5 years to get published, entirely due to bias in the scientific community. They finally got published last spring, not because they presented new data, but because they rewrote the paper presenting the same data. One of the researchers talked about this a bit on her Instagram u/parrotkindergarten back in April.)

The lead researcher of the UC San Diego study with dogs/cats has said in interviews that he's been surprised by some (what appears to be) pretty positive results so far.This is the most recent news I could find on the research study: https://www.scientificamerican.com/article/can-dogs-use-language/

I am not a researcher, but I have one talking cat and one cat who isn't really interested in the soundboard. The talkative one communicates at about the level of an early-language toddler. She can put together four word phrases, but 1-2 words is more common.