If you are in the teacher's class, you could always ask to pull these students and others for small group time. Ask her to see if she would mind you doing this. The small group time could occur after a test or assignment. The students would then be offered some accommodations. This is a serious issue and if not addressed these students will fall into the educational gap.

An ESOL teacher or instructional coach or administrator needs to get involved. These students need extra support to figure things out. They definitely need instructions paraphrased and writing assignments scaffolded. The administrator should ask to look at these students grades and question what is taking place in this classroom for these students.

Certainly ignoring children who are not learning is never going to encourage them to learn. It can be hard to teach if a language barrier is so intense that comprehension between student and teacher is not smooth. I believe that it is up to the teacher to start addressing it as soon as possible, and work extra with those students to help them gain the vocabulary and fluency they will need to progress. It sounds like Mrs. F is somewhat set in her ways and unwilling to make those compromises of her time and energy to allow those students the chance to flourish, and unfortunately I do not know how to bridge that gap, since it seems like it is a matter of her perspective more than anything else which is causing the achievement gap for those students.