This, alas, is one of the problems with being someone who tends to not talk much and rely on a lot of non-verbal communication. Answering with a nod or a gesture rather than a word is just habit, and he does it unthinkingly.

"Hi," he says. With another nod of the head that - of course - Rezo can't see.

Eventually, Link is going to realise how much of a problem that is.