"What is a light-year?," went one of his questions the week that the Star Wars prequel came out. The woman he asked professed ignorance. He needled her for a while before he gave her the right answer, "the distance that light travels in a year." Then, he asked her the follow up. "So, what is a light-sabre?". "The distance that light travels in a sabre?," she wondered. That girl was probably among the brighter people to whom Leno puts his questions.
All good fun. But a fellow who does this ought to be more careful about the things he says. You know, people who live in glass houses, kind of thing.
Thrice in a recent show, he talked about China's "nu-cu-lar" espionage. A former president of the United States (Nixon? Johnson?) also mispronounced the word, so may be it is an epidemic. The next time he goes Jay-walking, he should ask people to pronounce "nuclear". Maybe we could have fun of the Dan Quayle-potatoe kind.