I have been using Rich's material to supplement my training for years. His material is some of the best around and fits well into anyone's system. He is also one of the nicest guys around, very down to earth and generous with his time and knowledge.
As far as the language goes, he purposly uses curse words during his seminars and instructional tapes. His reasoning is that language is something that people will use to try to intimidate you or humiliate you in the street, being loud, cursing and calling you names is something that will occur in an attack. He tries to get his students used to that type of language and uses is as part of the training process.
Everyone who attends his seminars and classes are adults, nasty language is part of the real world and real world attacks. His speaking and teaching style is informative, interactive and very good as far as I am concerned.