Rajesh Koothrappali
Rajesh is not one to mince his words, in fact, when he's in the presence of Penny he doesn't use any words at all. According to his best friend Howard, this is because he's "kind of a nerd".
When Penny's talking to Raj he tends to drift off with his own thoughts, which have centred round his desire for an Indian wife to sing lullabies to his non-existent children. Hmmm.