顶,官方(指消光官方,我在那边提问了,客服发邮件回答我了)客服说的是Perform the following steps, please
Open Epic Games Launcher
Click on your profile icon (upper right corner of the window)
Select settings
Scroll down
Select the game
Check the Additional Command Line Arguments checkbox
Insert -epiclocale=xx , where xx is your language shortcode (eg. en, de, es, pl, ru)
Enjoy!