This is all about shifting focus. If a deep voice is not your natural voice, then you have to focus (even subconsciously) to deepen your voice. That act temporarily helps to make you focus less on stutter and focus on creating those deep tones. It works. Whenever I have a cold I take advantage of that rough/deep voice. I even jokingly mention during our meetings “my apologies if sound like a budget Sean Connery”. 😆