Be quiet vs Keep my mouth shut

When to use each in English, with meaning, register, and examples.

Be quiet

Top 2,000 (common)

Keep my mouth shut

InformalBeyond 10,000 (less common)
Most formal: Be quietMost common: Be quiet
 Be quietKeep my mouth shut
Pronunciation🇬🇧 //biː ˈkwaɪət//🇺🇸 //bi ˈkwaɪət//🇬🇧 //kiːp maɪ maʊθ ʃʌt//🇺🇸 //kip maɪ maʊθ ʃʌt//
MeaningStop making noise.to not say anything
ExampleThe teacher told the students to **be quiet** during the test.I decided to keep my mouth shut during the argument.
RegisterNeutralInformal
How commonTop 2,000 (common)Beyond 10,000 (less common)
Collocationsbe quiet in class, ask someone to be quiet, tell someone to be quietkeep quiet, keep to oneself, keep secrets
Antonymsmake noise, speak loudlyspeak, disclose
Common mistakesUsing 'be quiet' in a friendly context without softening the request., Incorrectly saying 'be quieted'., Confusing with 'be silent', which feels more formal.Using it in formal situations., Confusing with 'keep quiet' which may sound more neutral., Incorrectly changing the structure, e.g., 'keep my mouth closed'.
Usage notesUse 'be quiet' when asking someone to lower their voice. It's appropriate in both formal and informal contexts but can sound rude if used abruptly.Use this phrase in casual conversations when you choose not to speak or remain silent. It's less appropriate in formal settings.

See it in real clips

Be quiet
Keep my mouth shut

Frequently asked questions: Be quiet vs Keep my mouth shut

What's the difference between Be quiet and Keep my mouth shut?

Be quiet: Stop making noise. Keep my mouth shut: to not say anything

Which is more formal: Be quiet and Keep my mouth shut?

Be quiet is the most formal of these.

Which is more common: Be quiet and Keep my mouth shut?

Be quiet is the most common in everyday English.

Can you show an example of each?

Be quiet: The teacher told the students to **be quiet** during the test. Keep my mouth shut: I decided to keep my mouth shut during the argument.

Can I use Be quiet and Keep my mouth shut interchangeably?

Not always. Be quiet and Keep my mouth shut are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.

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