When used in a text, SFX means "Sound Effects." While this is its most common meaning in texting, be aware that it is a rare term, and it might mean something else. If our meaning does not fit, give the context of your conversation a name (e.g., love, sport, space, astronomy)...
He is portrayed as being intelligent, which is show with his by ability to understand the same language of the Danes that he encounters, even if it is an older dialect. As described in the text, “I found I understood them: it was my own language, but spoken in a different way” (...