It was when I was around 20 that I realized that I had to learn how to pronounce English properly. I was working as an English teacher, so my pronunciation had to be more or less correct. So I went to the library and found a book about the relationship between spelling and pronunciation and how to articulate each phonetic symbol. But, to my surprise, the book was based on the British accent. As I heard at that time that the American English is (supposed to be) taught in Japan, I was dismayed at the fact.
Now, I still teach English, and since it can very well be speculated that there will be many other occasions where I have to speak English than the school, I decided to learn anew the American accent of the language. So, my pronunciation is a distorted mixture of British, American and Japanese accents.
However, these days, I find myself growing fond of the British one. I can't explicate the difference between the British and the American, nor can I elaborate the reason, but the former feels familiar to me. Now I want to become a British in terms of the pronunciation.