How to practice? This is a question I get asked often from people who are trying to change their speech patterns. I find that l earning how to speak in a new accent is much like learning a musical instrument or dance. When you learn something new you’re creating new pathways in the brain. These pathways need to be reinforced in order to stick. As you are learning how to better pronounce sounds and phrases using the American English accent you are retraining the language centers and the movement centers of your brain.
Pathways are created in our brain when we’re infants and reinforced by family or caregivers. Sounds not in the native language are “forgotten” and become labeled as “foreign.” Because learning new sounds as in learning a new accent requires new movement patterns as well as new ways of thinking about different sounds it takes consistent repetition and reinforcement. You do not need to spend hours or even one hour per day learning better American English pronunciation. As with many things “less is more.” This is why I recommend practicing with a video, a voice recorder or at the very least a mirror. Fifteen to twenty minutes 3 to 4 times a day will create the best results. Listen to yourself and compare your pronunciation to that of a native American English speaker. Listen for your challenge sounds. Listen to the phrasing and linking of words. Do you produce these as the native speaker does?