A strange thing happened when my wife and I visited Cambodia, her home country, a few years back. People there were surprised to find that I could speak (some) Khmer, the Cambodian language, but that was to be expected. I do not exactly look Cambodian, after all. What was strange was that people were shocked that my wife could speak Khmer and she could speak it perfectly. This was strange because she was born and raised in Cambodia and Khmer is her first language.
When folks would hear her speak perfect Khmer, they looked confused and asked her where she learned to speak their language so well. She would explain that she was Khmer (Cambodian) and that her family home was only a few blocks away, right near the market. They found it near impossible to believe. It had been seven or so years since she had been back to Cambodia and something in her and about her had changed to the point that she no longer appeared Khmer to Cambodians.
If cultural identity is fluid and mutable, if it is not something we are born with or are stuck with for eternity, if it is learned, picked up from our environment as we live our lives, then we can change who we are by changing the environment we place ourselves in. As our environment changes, so does our cultural identity because we are not separate from that with which we surround ourselves. This means we must be careful where and with whom we spend our time.