A word or phrase to describe someone who is obsessed with words?

I want to be able to describe the love for, or obsession with, words. It may also be a condition from other's perspective.

It maybe because he is a lunatic who wants to aggrandize his vocabulary, a crazy person who can't forget the words he hears wafting around, or someone who wants to set a world record or something. Try fitting it in these:

He is a _ who can blurt a thousand synonyms for good.

He is so __ that he can be called a dictionary with a heartbeat.

He is showing what a _ he is.

If thesaurus was a ghost, he would be dwelling in that _'s body.

Any word or phrase would do.