I have 2 boys - 13 (ADHD) and 10 (not ADHD or anything) and neither of them talked like that at that age or now. I am wondering - could it be that your DS is hearing that kind of talk around him a lot (school, friends)? Do his peers talk that way? We moved 2 years ago and that type of talk is much more prevelant here than where we used to live. Not sure why. I bet he is picking this type of talk up from his peers and possibly his ADHD is contributing to his over use or impulsvive use of it.
Good luck!
Yeah, neither of my kids has gone through this stage, so from my point of view it is not an age or an ADHD thing. (Although, like Greyhoundmom said, ADHD could contribute to impulsive use of bad words.) I also agree with Greyhoundmom that he is hearing these words somewhere and maybe thinking that he is "cool" and gets attention by using them. Also I wonder if he is experiencing stress or something else negative in his life that is causing him to act out in this way?