If someone came into my clinic and refused to speak anything but Klingon, I'd throw them out on the street and say, "Get a real language and come back."
Seriously, people can't just demand to speak a fictional language. "This language is a work of fiction. Anybody wishing to actually speak it should not do so."
Only 2 (line-drawn) people I know of who know Klingon very well: Jason Fox and Comic Book Guy.