They identified nouns and adjectives in prairie dog communication, that also seems to vary with regional dialects. I'll try to remember to dig up a source when I'm not out and about later.
Edit: here's a not fully scientific link, but has names and links for people who want to go deeper in the science while being a decent lay person's overview.
Weren't science communicators talking about parts of speech in whale communication last year, too? They're using AI to identify patterns and variations in speech.
A rattlesnake can certainly communicate using sound, but is that language? Bright colors can communicate ideas of "do not eat this" across species as well, but they wouldn't fit my mental model of a language.
what is language than making sounds to convey meaning and then decoding said sounds to understand their meaning
human language is incredibly complex but a bee just buzzing a particular buzz that means "bear nearby" counts as a valid form of linguistic communication imo
Why do we use sound hmmm all over the world when thinking about something? Was there just first proto language that had all these onomatopoeias built in or were they invented independently because they excite neurons in same way, mood regardless of culture?
Maybe it also has to do with the human anatomy? Like, when people are thinking they probably have their mouth closed and maybe even purse their lips. The sound you can make in this pose is really just hmm I guess.
OK yeah, the next question would then be why we use certain facial expressions...