Formal:
* Verbose: This is a very common synonym, meaning using more words than necessary.
* Prolix: Similar to verbose, but with a stronger implication of tediousness.
* Circumlocutory: Using an indirect or roundabout way of speaking.
* Loquacious: Tending to talk a lot, but not necessarily in a negative way.
* Sesquipedalian: Using long words, sometimes unnecessarily.
Informal:
* Wordy: Simple and straightforward, meaning using too many words.
* Rambling: Going off on tangents and not sticking to the point.
* Chatty: Speaking in a friendly but perhaps overly casual way.
* Garrulous: Excessively talkative, especially about trivial matters.
* Windy: Similar to "long-winded" but more informal.
The best synonym depends on the context and the desired level of formality.