A question that comes up occasionally is if it is “easier” to learn an accent that is close to your own accent. The answer is not as straightforward as you may think.
Speaking is a physical task and we use a lot of muscles to manipulate airflow and vibrations into meaningful sound. In the same way you would train your muscles if you took up a new sport, you must train the muscles in your mouth to create the shapes that produce the sounds used in your target accent.
If you are learning an accent that is far removed from your own, your brain thinks “Oh this is NEW” and so it can easily distinguish between your habitual way of speaking and the new accent. If the accent has similar sounds to ones you frequently use, your brain has already learned where that sound “should” go and so can have a harder time subtly shifting it.
Add on top of this emotion and movement and your brain is using all of its power keeping you in the scene that it doesn’t have the capacity to register the subtle changes.
How do we combat this?
Practice! Once you find the new oral posture of an accent, practice talking through that set up – even words that sound similar. Your brain needs time to register this as a new normal so that no matter what happens physically, your dialect will not be compromised.