When you're multilingual, you'd switch between languages on the fly, mid-sentence even, just because the words in other language come to your mind quicker, seem to better match nuances, etc.
I concur.
Consider TFA. The symbols are not converted to from ASCII smileys and are used like an extension of the charset. Conversely, I remember web chatrooms in the mid-00s, where a colon-paren would always be converted to the service's pallette's rendition of an emoticon, pretty color and 3D to beat.
Plus, there's a question of how people use them, but that distinction I think came later
Isn't it?! There's plenty of talking about how "we're regressing to hieroglyphs", but that doesn't capture the nuance in usage of emojis in different languages.
Your example expands well to old-school emoticons. Where I live, an "xD" serves as a laugh and is used in rather general way. Meanwhile in the Anglosphere it's stereotypically associated with specific demographics