Actually, that's not what parent comment meant. By Taiwanese he meant the Taiwanese Hokkien dialect, which is what is spoken by many Taiwanese at home that is mutually unintelligible from Mandarin. It has words that do not correspond neatly to Mandarin or classical Chinese, and so historically, writers have invented characters specifically to write Min languages.

It's unfortunate that awareness of the many Chinese dialects/languages is pretty poor in the Anglosphere, and parent comment could be clearer with what he meant by Taiwanese. It was obvious to me that it was Hokkien that he was referring to, but that is only by virtue of me having familiarity in the matter.