This won’t help “fix” the problem but one thing that you could do is have your parents (and/or you) contact the teacher and explain the situation, letting her know what triggers it and out of respect for you the teacher should stop putting you in these difficult moments. School is hard enough all on its own add a speech or anxiety issue into it and you’re just dealing with unnecessary stress if it can be avoided. My son stutters and every other year I have to send a new teacher an email asking them to not call on him in the middle of the class unless he is volunteering (which he does do a lot- it’s the being put in the spot out of nowhere that makes his stutter worse) and they always understand and have no problem adapting