In the Chinese film Ip Man there's a scene where the titular character confronts a friend of his who is working with the occupying Japanese army, serving as a translator despite being a resident of the town whose citizens are being oppressed.
During the scene, where Ip Man calls his friend a traitor and his friend protests that this is the only way he can feed and protect his family, there's a switch between languages which isn't acknowledged by the subtitles (at least, in the version I was using). As Ip Man's friend is angrily protesting that he's not a traitor, while Ip Man himself walks away in disgust, the last line that his friend yells ("I'm a Chinese man!") is spoken in Japanese, despite the rest of the conversation being in Cantonese.
That he protests his nationality in the language of their oppressors changes the context of the scene, or at least that line, something which seems to be lost to audiences who don't notice the switch.
