Spectators occupied small, portable bleachers between the practice fields and the track. Again I was struck dumb by the language I heard coming from the fields behind me. He showed no restraint whatsoever in the presence of the public. Scriptwriters supposedly create realism when their characters talk trash. To my ears such dialogue speaks to a writer's ignorance and laziness more than to efforts to portray memorable characters or absorbing scenes.
Language contains such a variety of choices, fascinating nuances and power.
Along with our responsibility to teach children to use language clearly and accurately comes the responsibility to teach them about social context. We spent a considerable amount of time in our household teaching our children the differences between standard English and slang, informality and trash. They, in turn, as only children can, reminded us of the rules, every chance they got. You state that your son continues to defy your rule against the use of foul language at home. No matter what children in the neighborhood or at school are saying and doing, house rules are house rules.