If a child has always been told to "pee pee toilet," or "flush the potty," their reaction to you saying, "Flush the commode" is probably not going to be what you'd like it to be.
As someone who works in a child care center thriving with diversity, I am paying very close attention to language and the context in which it is used with small children. While children absolutely come to "learn," they also come to use with prior knowledge and experiences they are trying to make sense of within the context of school. Things that 'work' at home or are cute at home are not tolerated at school.
Case in point, the adorable child with ample (and oh so squeezeable) cheeks who has had her cheeks pinched her entire life by family members cannot come to school and squeeze the cheeks of her peers. They simply won't allow it, even though she may be doing this to show affection and love much like her family members do. It's kind of a tough thing to learn, that what's okay at home doesn't fly at school.