This is one bit of awkwardness that I actually found to be mostly a strength in After Earth, I think. Kitai is presumably in his tweens or early teens, and so his general awkwardness in expressing his emotions and communicating his desires to his parents is appropriate; the clumsiness with which Jaden Smith delivers his dialogue could be ineptitude but even if it is, of which I’m not entirely convinced, this makes for a realistic portrayal of a period in a boy’s life that is usually considered an awkward phase.
It also explains the motivation behind, or maybe is a result of, his father’s general disappointment with him. He’s reactionary and overemotional and prone to outbursts despite his insistence that he has the capacity to be a strong officer like his father. It’s weird seeing a brash teenage boy brought to tears, and in this movie’s case, that’s a good kind of weird. It’s just unfortunate that there’s so much other weird and offputting stuff going on in After Earth that ultimately end up detracting from the story for too many viewers. There are times when it seems like Shyamalan’s collaboration with the Smith family may seem like a return to the Sixth Sense form of years past, but for most of the movie, the dominating sense we’re left with is bafflement.