- (idiomatic) To talk more loudly or plainly.
- Could you speak up? I can't hear you.
- (idiomatic) To make oneself or one's opinions known; to advocate or assert oneself.
- I feel that somebody has to speak up for those oppressed by the system.
- Speak up if I'm bothering you.
to talk more loudly or plainly
to make oneself or one's opinions known