Formal:
* Loquacious: This word implies a fluency and ease in speaking, often with a great deal of wit and charm.
* Voluble: This word suggests a rapid and continuous flow of speech, almost like a waterfall.
* Garrulous: This word often carries a negative connotation, implying that the person is talkative in a rambling, pointless, and often annoying way.
Informal:
* Chatty: This is a neutral term for someone who enjoys talking and is often friendly and engaging.
* Talkative: This is a simple and straightforward word for someone who likes to talk a lot.
* Motormouth: This is a more informal and humorous term for someone who talks incessantly.
* Gabby: This is a casual word for someone who is talkative and enjoys chatting.
The best word to use will depend on the specific context and the tone you want to convey.