Karena Ng (吳千語) revealed she filmed fighting and slapping scenes but no vulgarity when filming the movie (女子監獄) in 2018 at a dinner banquet on 18th March 2019. She said: “It does not matter if I need to speak vulgarity as I do say it occasionally in reality, but not in front to the public.” Karena felt it was normal to speak vulgarity in English but not to scold people and venting the frustration only.

Source: https://ol.mingpao.com/ldy/showbiz/latest/20190319/1552975948995/%E5%90%B3%E5%8D%83%E8%AA%9E%E6%8B%8D%E6%88%B2%E7%84%A1%E5%8C%85%E8%A2%B1%E5%94%94%E4%BB%8B%E6%84%8F%E8%AC%9B%E7%B2%97%E5%8F%A3-%E6%88%91%E5%B9%B3%E6%97%A5%E4%B9%9F%E6%9C%89%E8%AA%AA