In many ways, I understand how language barriers could be seen as an immediate disadvantage. I think most of this is due to the lack of time for education and the number of students one teacher is in charge of in a class.
In a perfect educational world (whatever that is), a language barrier would actuall enhance the learning experience because both teacher and student would rely on one another and education would be happening two ways. It would take more time. And likely, it wouldn't work well unless the student-teacher ratio was very low.
This can be a big problem. When you have trouble in a subject, broken English can make it even harder to understand. If possible, you might try sitting closer to the front so that it is louder, and even transferring to another class if you can.
I guess this is a problem that occurs all over the world--including the United States. When I was in junior high school in the 1960s, my English teacher was a native of North Carolina, and her Southern accent was so thick that I had problems understanding her. But she proved to be a great teacher, and I eventually learned the nuances of her Carolina twang. Give it a little time, and hopefully you will one day be able to understand your teacher's broken English and recognize--again, hopefully--that his teaching skills are worth the trouble.
I've had teachers (in elementary school) who didn't speak good English and lab assistants in college who had very thick accents. Sure, it's harder to understand them, but it's helpful too. It's good to learn to understand people who speak differently because you'll surely encounter them in life.
I fully agree with bhawanipur (post 5). The situation is exactly the same in Pakistan, especially in the rural areas. In public schools it is hard to find a teacher who can speak English fluently, some of the English teachers may speak English with bad accent and grammatically wrong sentences. In public colleges, though the medium of instruction is English but even there only few deliver their lectures in English and prefer to use the national language Urdu or the local language.
However, in public schools and colleges the situation is much better and one can find many teachers having good command of the language.
In India, specially in the public schools, we hardly find teachers who can speak English fluently. Even in colleges, teachers other than of the English are not fluent in English. Because in most of the states, students are taught in their own mother tongue. Therefore, it becomes a great problem for students to understand teachings in broken English. Teachers translate from his mother tongue and teach. Teachers should be imparted training to acquire fluency. However, in English medium schools are less effected by this problem.