Some teachers are altering their accents in class to avoid negative reactions, a small study suggests.
One teacher, from Bristol, told researchers he did not want to be seen as "a village idiot" or "a thick yokel who lives on a farm".
Another, from the Midlands, said she was told to change her accent or to "go back" to where she came from.
But teachers and students felt they should be free to speak in their own accents, the study found.
Nine teachers and 55 students from three Manchester schools, interviewed at length for the study, did not support the idea that a "standard" British accent should be adopted in class.
This might be something similar to received pronunciation, which some see as commanding respect.
Department for Education guidelines require teachers to promote "high standards of literacy, articulacy and the correct use of standard English".
But research author, Dr Alex Baratta of the Manchester Institute of Education, points out that the guidelines do not cover the issue of accents, questioning whether it is an area that is "too controversial" or "too complex" to address.
Two of the nine teachers in his study admitted to "consciously modifying" their accent in preparation for a teaching career.
A teacher from Bristol explained why he changed the way he spoke.
"The Bristolian accent has lots of connotations," he said.
"Normally, things like village idiot, yokel, farmer, you know, friendly, but stupid ... agricultural ... so because of that once I came into contact with people that had softer accents and accents from elsewhere.
"You have these kind of stereotypes that exist and it wasn't doing me any favours."
'Tug of war'
Another, from Salford, told how she had toned down her accent so as to be "a model for the girls" in the private school in which she worked.
Her change was also based on making her accent more like those of her pupils, which "while regional to Manchester, were certainly not broad" she said.
The author also gave the example of an art teacher with a "quite strong" south London accent, who was asked to write the word "water" with a capital T, to remind her to pronounce it.
And yet nearly all teachers and students involved in the study felt they should be free to speak in their regional accents.
However, Dr Baratta suggested some teachers faced a "potential tug of war" because of the way their particular accent is viewed and felt a pressure to change the way they spoke.
"While there may be a desire to be true to one's linguistic roots," he said, "people might have to consider this desire against the potential for the negative connotations of one's accent, within a profession in which such stereotypes might seem incompatible."