Do Taiwanese speak mandarin?
Just a minority speaks Mandarin natively. The majority of Chinese speakers speak Min Nan natively. There is a minority who speak the native Taiwanese languages, which are not Chinese or even related to Chinese. They are the Austronesian languages Rukai, Atayal, Paiwan, Tsou, etc. The “native” Chinese language of Taiwan is Min Nan. When the Communists took over the mainland, the island was “invaded” by refugees who spoke Mandarin. These refugees took over the island and imposed their language on the Min Nan and Austronesian population.