Do facial expressions have well-defined meaning? Where does one look up the emotional context that a specific facial expression conveys when you say a thing to

Do facial expressions have well-defined meaning? Where does one look up the emotional context that a specific facial expression conveys when you say a thing to a person in real life? How can you be sure that emojis aren't conveying emotional context to you? It's not possible to rewind reality to the time before you received that text, and replay it again without the emoji to see the difference. I posit that emojis do in fact add emotional context, and if you could run that experiment, that you would have a harder time deciding sarcasm, self-deprecation, humor in general, and a whole host of other emotions. They are becoming part of the textual grammar just like facial expressions provide grammatical context for sign language and can totally change the meaning of the same hand sign. Either you learn the emotional contexts, or you don't and suffer the social consequences. I don't see much that's changed, just that technology is still way behind in-person communication. Seems to be catching up little by little, though.