I read the post https://japanese.stackexchange.com/questions/60907/ and have a hard time understanding the meaning of "polarity" even after googling the term (I found "polarity item" but it seems unrelated?).
... Adverbs don't determine polarity of a sentence in Japanese unlike English. e.g ほとんど殺した means "killed almost everyone", not "almost killed".
Could you help me (a guy who is new to linguistics) understand it?