The loophole or twist here is that other languages means-no Korean, Japanese, mandarin, Cantonese, English, European languages or S.E.A languages; this leaves only Chinese dialects(excluding cantonese), Asian languages other than mandarin, Cantonese or S.E.A languages, plus South American not-spanish/portuguese. Then African languages.
I think there's no African speaking or south american/Caribbean native language speaking kpop idols nor asian(chinese not cantonese) dialect-speaking idols afaict.
So Katseye Lara who can speak Tamil(not sure how fluent tho) is my pick.