Because of your last words about your judgemental attitude against that person the supervisor, I truly hope your son develops a severe stutter. I will not give you any advice at all and hope that you get zero help. Stuttering is often caused by learning to speak too soon in life, im sorry your genes are bad and your kids are slow. Maybe then you can learn how it is for real, maybe then you can learn to change your view of a stutterer. Sincerely FU.