A user has requested that I share my thoughts on multilingualism and identity, so I thought I would take the opportunity of this post to do so.
When learning to speak another language, it is impossible to do so fully without learning completely new body language, mannerisms, etiquette, and customs. What is rude in your own culture may be polite in another; what is polite in your culture may be rude in another. Learning to be "rude" appropriately when speaking a new language can be very difficult for many people, as it requires one to go against practices that have become innate and instinctive.
When learning to pronounce and speak another language fluently, one cannot use the normal system of sounds one is accustomed to using. This means speaking another language without accent feels artificial (at first). It is almost as though you have to use someone else's voice.
Imitation is a fantastic tool for language learning. It's possible to identify different types of pronunciation, mannerisms, and habits that are tied to different groups of people. When acquiring a new language, you have to make the language no longer foreign. This means finding your own voice and habits within the context of the new language. Imitation can be a useful tool for that, but you must eventually find your own voice. It can be difficult, in part because most people look for the correspondence to be one-to-one. In other words, they want to act and function the same in the new language as they do in their own, which is impossible.
The path to multilingualism involves the difficult process of finding the right equivalents for our normal habits in the new language and culture we are learning. Being truly multilingual is like having multiple identities to a certain extent. In reality, it helps us question who we are, and we realize that the "I" that underlies our being is not tied to accent, speech, body language, or social habits. It doesn't change even when we put on the "identity" of a new language and culture. That is somewhat scary at first to confront, but it is also comforting when we come to know our unchanging core.