General "speak":
* Magsalita - This is the most common and general way to say "speak".
* Mag-usap - This means "to talk" or "to converse" and implies a back-and-forth conversation.
Specific types of speaking:
* Magsalita ng Ingles - To speak English
* Magsalita ng Tagalog - To speak Tagalog
* Mag-ulat - To report or give a speech
* Magtanong - To ask a question
* Sumagot - To answer
Other nuances:
* Magkwentuhan - To chat or tell stories
* Magbulungan - To whisper
* Magsigawan - To shout
* Magsisigaw - To scream
The best word to use will depend on the context of your sentence.