Rule 1: Open your mouth and move your lips when you speak.
Many languages don't require speakers to open their mouths and move their lips much at all. When they go to speak English, they naturally keep their teeth close together and their lips fairly flat. Does this sound familiar?
When you speak American English, opening your mouth and moving your lips is a must. If you watch any good public speaker, then you'll know what I mean. Pay attention to opening your mouth more when you say vowels. Creating a little more space in your mouth goes a long way in improving speech clarity.
Rule 2: Reduce your speaking rate
Many languages are spoken more quickly than American English. Chances are, your native language is one of them. Combine a fast speaking rate with an accent, and you have someone who Americans most likely have a hard time understanding.
Speaking more slowly doesn't mean speaking TOO slowly. It means slowing down enough so that you have time to form all of the sounds and syllables in words. People who naturally speak quickly often omit run their words together, so a sound or part of a word may be missing. Speaking more slowly can also mean that you pause more often when you speak, and always pause at the end of a sentence.
The nextt time you speak, keep these two tips in mind. They will help you reduce your accent and speak more clearly!