This article starts with the question, "Should a teacher who can't speak fluent English to her students be allowed to stay in the classroom?"
Short answer, no. Long answer, no, but you can't just fire someone. You have to take into account many factors, like the teacher's self-esteem, membership in a union, race and gender. The one thing you don't have to take into consideration: whether the teacher is any good at her job.
While pursuing my degree at Minnesota State University - Moorhead, I signed up for a class in "Computer Management". It was taught by a professor (I won't name him, but some of you will know instantly of whom I speak) who is of Chinese descent. He did not speak English. I don't mean to say that his accent was hard to decipher. I work in a company with many races represented; some of my coworkers are at times difficult to understand. But we communicate well and everybody always leaves the room with an understanding of what was said. Not so with this professor.
He literally did not speak English. His class consisted of him scribbling incomprehensible scratches on the chalkboard while mumbling incoherently. Occasionally he would turn to the class and say something unintelligible, then give this clipped sort of giggle. Then he would turn back to the chalkboard.
I passed his class with a B. I did this despite not getting better than a D on any test. This is because, in order to keep the natives restful, the class was graded on a curve like a horseshoe. Also, since know one I know actually failed the course, the curve also must have been manufactured in some sort of Lovecraftian dimension where F's become C's and everything else becomes a B.
I relate this story because it kills me to know that there are teachers like this, out there right now, teaching kids. I had the misfortune of running into such a teacher as an adult; I knew I wasn't going to get anything out of the class and was thus prepared to dismiss the whole thing. Children, though, look at teachers as examples of authority. They're supposed to be smart and infallible. Teachers like my Computer professor and the woman in the linked article can single-handedly kill a child's desire to learn.
Should a teacher who can't speak fluent English to her students be allowed to stay in the classroom? Let's stick with the short answer.