I know one of the themes of this movie is supposed to be something along the lines of showing the struggles of people in the world dealing with different languages. But it seemed to me the bigger theme is why you shouldnt make stupid decisions. I mean take for example the Mexican woman. She ended up deported, not because their was a language barrier, but because she thought it would be a good idea to cross an international border with 2 kids that were not her own, and then somehow try to get back into the US by driving through the border checkpoint with her drunken nephew, even though she (and probably he) were both illegal immigrants. Who in their right mind would think that this was an intelligent plan? Did she really think it would work? She didnt get deported because of language problems she got deported because she made a stupid decision.
Now look at the Moroccan boy. He decided it was a smart idea to take few shots at a bus full of tourists. He then decided to take shots at the cops who came to arrest him This whole thing was set up because his dad thought it would be a smart idea to let his young sons use a rifle. This lead to the death of his brother. This also wasnt caused by any sort of language barrier; it was caused by stupid choices.
Even Brad Pitts kids going missing in the desert was caused not because of any language barrier but because he thought it would be a good idea to leave his kids with the nanny with no back up plan for someone to look after the kids.