how can i talk to him beside letters

Very occasionally he does fan/autograph signing events, and whenever he does a play, he signs autographs for những người hâm mộ outside the stage door. Apart from those (where you'd only be able to have a few giây with him) there really is no way những người hâm mộ can get to talk to him.

As far as I know, David Tennant doesn't have an e-mail account that is opoened to the public.

Neither is his phone number. LOL!

Well, depending on what country bạn are in, if he happenes to be a guest hoặc guest dj on a radio program were bạn can call in and speak with him.

Or, bạn could try yo contact any studio hoặc go through his agent c'mon! all actors have an agent.

but otherwise I don't have a clue.