speak louder; raise one's voice; "The audience asked the lecturer to please speak up
If you speak up, you say something, especially to defend a person or protest about something, rather than just saying nothing. Uncle Herbert never argued, never spoke up for himself
[ 'spEk ] (verb.) before 12th century. Middle English speken, from Old English sprecan, specan; akin to Old High German sprehhan to speak, Greek spharageisthai to crackle.