[blparent] language use concern

[hina altaf]

Hi friends,
I am having this issue with my 4 year old preschooler very regularly
and both I and my husband have tried every technique. None of us use
any bad or wrong words around our son, however, he picked up words
from my friend who is very rough and always uses all kinds of words
around little kids. He has been saying "stupid" this "stupid that" We
ignored it, corrected him, told him this is wrong and just completely
ignored and did not respond so that he may stop using it, but nothing
worked.
Any suggestions you guys have or any techniques that worked for you?
Hina.