The behavior should continue to be reported to the administration. If the teacher has already been warned to stop doing this then it should be reported until action is taken. Teachers should not be gossiping about their students for any reason and the behavior needs to stop so that the behavior does not present itself in other teachers.

She needs to be reprimanded. There are consequences for her actions Make sure she knows them, and then enforce them. Stick to it.

I would try to warn her about her speaking like that about her students and if the other teachers feel the same about this then we could talk to administration together and hopefully it'll bring her to stop.

In this case, I think another teacher that is hearing these comments everyday needs to report it to someone higher up, maybe the principal, and see what can be done.

There is nothing wrong with a teacher being frustrated with a student and how they act but speaking poorly about them is not the way to deal with their frustrations. If they're just asking for advice from other teachers, then I wouldn't see anything wrong with it but if they're being rude or insulting the students, I would definitely say something to them. If they don't stop then I would go a step higher and ask administration to step in.

In this case, I would take my complaints to the principal for a resolution.

I would first remind her that students all have unique skills, and if she cannot say nice things then she should not say anything at all. I would also remind her that she has been warned about this behavior and you would recommend stopping so as to not get in trouble again. Then if it did not get better, I would go to admin and make them aware of the behavior. It is unprofessional, inappropriate, and downright wrong. I feel sorry for the students she is labeling; other teachers may take her word as truth and treat them as "bad" and "negative."