Dear (insert teacher name),
I understand the United States of America is a land of opportunity, a place for people to feel free and save from those who oppress them, but if you are going to come to America to teach a class other than foreign language, please learn how to speak CLEAR English. I don't mean to sound rude, but as a student who is trying to learn a new and/or difficult subject matter, it is hard to fully grasp the concept when I don't fully understand what you are saying. I came to college for an education, but when I can't learn because I don't understand the words coming out of your mouth, it makes it that much harder on me to do well in your class.
I understand you most likely know the material you are teaching very well. I understand you are doing this job to make a living. I understand you do not mean to make the class harder than it should be. Unfortunately, I am just not grasping the concepts, for I don't comprehend the words coming out of your mouth.
I appreciate all that you are trying to do, but learning to speak English and speaking English just seem to be two very different things for you. Enunciation and Clarity are key when trying to teach students. This can also go for those who have very thick accents, such as Southern Americans, Northern Americans, British people, etc.
Once again, I hope you won't take offense to this, but I have no idea what you are saying!
Sincerely,
A student trying to learn