General synonyms:
* Talk
* Say
* Converse
* Communicate
* Express
* Utter
* Articulate
* Pronounce
Formal synonyms:
* Elucidate
* Enunciate
* Discourse
* Orate
Informal synonyms:
* Chat
* Gossip
* Jabber
* Yack
* Blab
Synonyms related to specific situations:
* Whisper: To speak softly and quietly.
* Shout: To speak loudly.
* Mutter: To speak in a low, unclear voice.
* Declare: To state something formally or officially.
* Confess: To admit to something wrong or embarrassing.
The best synonym for "speak" will depend on the specific context and the intended meaning.