While I ponder the answer to that question, here is a quasi Luke quickie. There is a phrase he uses from time to time that I absolutely adore. It is what he says when telling me about preschool usually. He gets very excited and says "Oh and mom here is something very exciting that Miss Fitzsimmons told me today, and actually it makes me a little scared too, but...."
The first time he said that he was telling me about going on a "bear hunt" with his class and another time it was about the teacher telling him that the school year was almost over. Luke is, in the immortal words of Uncle Rico, just a tender little guy :)