From my point of view, if you can speak the language, you are assimilated well enough. Everything else should be optional: how you dress, the food you eat, your religion, and so on.

Basically, you just need to be able to communicate properly with others. Also, I would say that English does not need to be perfect all the time. If the person you are speaking with can understand you, that's good enough.

People might disagree with this. However, I believe in giving and getting enough freedom to be allowed to be an actual individual.