This is kind of old now and no one probably cares, but on Saturday Phase Connect's Remilia and Rie played the bomb defusing game and at the end had some rounds in Chinese-only. They explained that they'll be doing it in "our mother language" but they speak different dialects
(1:32:03). They decide on Mandarin only and to me it sounds like Rie is speaking naturally, but Remilia struggles with it. Hopefully this means Remilia is the better kind of Chinese and not mainland, as I've been enjoying watching her and would hate to have to stop because she turned out to be the enemy.
Saying that, shortly after, they suggest playing in Japanese-only, and Remilia declines, saying "Japanese is hard"..in Japanese, while clearly knowing how to speak it
(1:44:37) it, so I dunno.