What word would describe a very talkative person?

There are many words to describe a very talkative person, depending on the nuance you want to convey:

Neutral:

* Talkative

* Loquacious

* Voluble

* Chatty

* Garrulous

Positive:

* Articulate

* Eloquent

* Expressive

* Conversational

* Communicative

Negative:

* Rambling

* Windy

* Verbose

* Prolix

* Gabby

* Motormouth

* Chatterbox

* Blabbermouth

The best word will depend on the context and the specific tone you want to achieve.