In the films, and the EU, we see many examples of characters not being able to understand one another: Luke can't really understand Chewie, goes back and forth on how well he understands R2D2, presumably requires a translator when speaking to Jabba (he gives no indication that he can understand Huttese), etc...
Now, sure, we also see that some characters understand many languages: Han understands, Chewie, Greedo, Jabba, and probably a couple of others.
Yet there's no language mechanic for EotE...obviously, it could be handled as just a GM thing (you either do or don't understand this character), but how do you handle it?
Personally, I'm not a fan of everyone always being understood, but neither am I a fan of it being left entirely up to GM fiat.