I wouldn't say it comes from Korean, more like it and its analog in Korean probably have a shared origin due to the mixing of ancient Koreanic and Japonic peoples pre-migration and during migration. It may have come from a different language that doesn't exist today, it may have originated in proto-Korean or proto-Japanese, or Koreanic and Japonic language speakers may have just changed each others language in a way which caused the particle to emerge in both languages (which is certainly plausible given how much they influenced each other's grammar in general).

[–] [email protected] 3 points 7 months ago

You're right.

[–] SeabassDan 2 points 7 months ago (1 children)

So you're saying it still could've come from Portuguese??

[–] [email protected] 8 points 7 months ago

From what I've researched online, the consensus among linguists is that it is not Portuguese in origin. I haven't found anyone opining this other than this tumblr user in fact. Anything is possible, but this seems completely ungrounded.