Because Kanda is as foreign as they come.
Allen doesn't know how to react to Kanda; he throws off Allen's sense of balance, makes him get that queasy feeling like when you're falling.
(Allen's always falling when it comes to Kanda.)
Kanda is a foreign taste on his tongue. Kanda, Kanda, Kanda. Bittersweet, with cutting words and cruel remarks, and Allen's not quite sure what part of him is sweet, exactly, but he's determined to find out because he knows it's there-- Kanda is like ice, and ice can always be melted.
Kanda is a foreigner, but Allen always feels foreign when he talks to Kanda. It's like he's dipping into a world he doesn't know anything about, and he never knows what to expect. Sometimes he's pleasantly surprised; other times he finds Mugen at his throat and Kanda a million miles away.
He'd like to keep Kanda close.
Allen has always been a people person, but he's never seemed to be a Kanda person, and he wants desperately to change that. Kanda is a foreigner, and Allen's not sure how to deal with him, because he's never met anyone like Kanda before, and he probably never will. (But that's alright, because Kanda's the only Kanda he wants anyway.)
It's a slow process (understanding Kanda, that is), like learning a foreign language. All the words feel strange and inadequate in his mouth, and he stutters and stammers and trips over them. Allen wonders if Kanda understands him at all, understands what he's trying to do, and if he does, why he lets Allen continue.
Maybe, maybe, he is just as lost in the world of Allen Walker as Allen Walker is lost in Kanda Yuu.
A/N: Just a quick drabble that sort of wrote itself while I was working on my other Yullen fic. I'm quite pleased with it. :D
Things that write themselves tend to sound truer... if that makes any sense to you other writers out there.
Anyways, hope you enjoyed. Please drop a review if you did (or didn't).