It is difficult to speculate, other than your wife is suffering from depression. Whether this is in response to her environment, her expectations, or a chemical imbalance, I'm not sure, not knowing her and not being medically-trained.
I do wonder whether she has articulated any of her frustrations, with words rather than fists. What does she want? What would she like her future to be, now she has lived with you for a few months? Does she want to work? Does she want to study? Can you have these kind of discussions? Can she articulate her feelings to you?
I teach young children, and find that physical aggression is often the only way some children can communicate their frustrations. This is because their language is inadequate to express their emotions. I am not suggesting your wife is a child, but the language barrier, coupled with her lack of an outlet to communicate her frustrations, plus a possible cul-de-sac in her expectations for the future could be an explosive mix.
When I speak with my wife about our future, it is sometimes difficult to find out what she wants. She defers to me, she says we can live anywhere, she will follow me, she is happy if I am happy, I can get any job, she doesn't mind. But I tell her that I need to know what she wants. And after a lot of discussion, sometimes, I actually find out, and then I tell her how much I appreciate her telling me.