In addition to the accent, which in some regions in Brazil, the accent is not very similar.
Some words have different meanings and are even funny.
One example is the word bicha (fag). In Portugal it means queue while in Brazil, in addition to being the feminine of "animal", it is also a vulgar term for a "homosexual".
Ah okay. Yes I can see a lot of that being a problem. It is why we need people to fill this with a lot of stuff from their language.