One for whom emoji happened well into adulthood, and they start tacking them on awkwardly and redundantly.
One for whom emoji has always been almost as accessible as the latin alphabet, and touchscreen keyboards are so shit that emoji themselves become slang for concepts that they're only obliquely related to.
Yes. And there's a younger generation (Gen Alpha) using slangs such as "👁️👄👁️" as a synonym for "😮" (if I understood correctly, because I'm not Alpha, I'm Zennial).