How do we teach self advocacy?

One student I work with is working hard at being the class clown. He's found this identity for himself and spends much of his time working on getting his peers to laugh at him. Although he is funny it is tough to watch such a great kid spend so much time trying to be funny when he has so many other great qualities. He also has a specific learning disability.

The other day during a lesson he was attempting to make the class laugh instead of answering a question. His very skilled teacher was managing to completely ignore the attempts at humor and keep him focused on the question at hand through restating her question and asking him to rephrase what a peer said. 

Finally he said, "I can't understand what my friend says. He speaks too fast." 

 His teacher and I were taken aback for a moment. "Thank you for telling us that," she said, and restated what the peer said for our friend.

It was such a clear moment of self advocacy. Instead of trying to distract the class and hide his struggle to comprehend oral directions, he took a moment and honestly explained the problem.

How do we harness that self advocacy? How do we help him understand that there isn't anything wrong with not being able to process things differently, it just means he needs a different set of instructions? 

How many times a day is his humor and willingness to get in trouble masking his real difficulties in the classroom? How do we reach him?