I won’t go into the reasons why you’re doing that. Instead, I’ll just focus on your plans, because I don’t think a gradual change of accent will go unnoticed. Just do it. Embrace the American accent you love so much and live it to the fullest. And if anyone asks you what happened, just say you’re tired of your own accent and are trying something new. Explain it clearly to others and own up to it. This will make you feel good because you’re being honest by telling others why you have decided to change.
However, you should bear in mind that a language is much more than just an accent. It also includes people’s choice of words and idioms and expresses the way they see the world. It would be strange if I decided to speak Brazilian Portuguese with a Portuguese accent (from Portugal). Those who know me would be confused because this “Portuguese character” in me speaks the local language perfectly with the wrong accent. How come?
It is the same, sorry. When you hire a third party to build or expand your business, you’re accountable for what happens under your nose. Simply pointing fingers to outsourced work as if it were beyond one’s control does not cut here. If you wish to operate in Brazil, you must comply with local legislation. And stating that some companies break the law is the same as saying that some people are turning a blind eye to the legislation, too. BYD management must choose which side of the legal fence they want to be. Cheers!