Oh yeah. I call it tactical fluency. I too noticed that whenever I talked in an American accent or like Littlefinger from game of thrones I never stuttered. Its really effective for things like one on one conversations, job interviews, presentations or even talking to girls. Unfortunately it doesn't work for me when I'm in groups or when the pace of the conversation is fast. Its also hard to make it work for stuff like jokes where u execute the punchline. What has been your experience with that?