Use 'speak up' when someone can't hear you, not when you want to share your opinion.'Speak up' means to increase your volume, while 'speak out' means to share your opinion.
to say what you think or feel, especially if it is important or difficult.
It's important to speak up if you see something unfair happening.
A: I don't agree with the new rule, but I'm nervous to say anything. B: You should speak up. Your opinion matters.
In my opinion, students should speak up in class discussions to share their ideas and learn from each other.
Common mistake
✗She spoke up her opinion at the meeting.
✓She spoke up at the meeting.
'Speak up' is used alone here — don't add 'her opinion'.
Tell it apart
She finally spoke up about the bullying.
voiced it openly
She spoke up so we could hear.
talked louder — sense 1
Use 'speak up' when you want to say what you believe, especially in a group or public situation.'Speak up' here is about sharing your opinion, not about volume.