All of a sudden vs Immediately vs Rapidly vs Suddenly

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

All of a sudden

Top 2,000 (common)

Immediately

Top 1,000 (very common)A2adverb

Rapidly

Top 1,000 (very common)B2adverb

Suddenly

Top 1,000 (very common)A2adverb
 All of a suddenImmediatelyRapidlySuddenly
Pronunciation🇬🇧 //ɔːl əv ə ˈsʌdən//🇺🇸 //ɔl əv ə ˈsʌdən//🇬🇧 /["/ɪˈmiːdiətli/"]/🇺🇸 /["/ɪˈmiːdiətli/"]/🇬🇧 /["/ˈræpɪdli/"]/🇺🇸 /["/ˈræpɪdli/"]/🇬🇧 /["/ˈsʌdənli/"]/🇺🇸 /["/ˈsʌdənli/"]/
MeaningUnexpectedly or very quickly.right away, without waitingquickly or fastHappening quickly and without warning
ExampleAll of a sudden, it started to rain heavily.He answered the question immediately after it was asked.to **increase/spread/expand rapidly**I **suddenly realized** what I had to do.
RegisterNeutralNeutralNeutralNeutral
How commonTop 2,000 (common)Top 1,000 (very common)Top 1,000 (very common)Top 1,000 (very common)
CEFR level-A2B2A2
Part of speechadverbadverbadverb
Collocationsall of a sudden, a loud noise, all of a sudden, they appeared, all of a sudden, it happenedrespond immediately, act immediately, notify immediatelygrow rapidly, change rapidly, develop rapidly, increase rapidlysuddenly appear, suddenly realize, suddenly stop, suddenly change
Antonymsgradually, slowly, over timeeventually, laterslowlygradually, slowly
Common mistakesUsing in overly formal contexts., Confusing with similar phrases like 'suddenly.', Omitting 'of' in the phrase.Using 'immediate' instead of 'immediately'., Confusing with 'eventually', which means later., Incorrectly placing 'immediately' at the end of a sentence.Using 'rapidly' as an adjective instead of an adverb, Confusing 'rapidly' with 'quickly' in formal writing contexts, Overusing 'rapidly' in informal conversations where simpler words are betterUsing 'suddenly' with the wrong tense (e.g., 'sudden' for past actions)., Confusing 'suddenly' with 'sudden', forgetting it needs to modify verbs., Using 'suddenly' too often, making writing sound repetitive.
Usage notesUsed to describe a change that happens suddenly. Suitable for both spoken and written English; avoid in formal writing.Use 'immediately' to emphasize urgency or promptness. It's appropriate in both spoken and written English, but avoid in very casual contexts.Use 'rapidly' in contexts where something is happening very quickly. It's more formal than 'quickly' and might not be suitable for casual conversations.Use 'suddenly' to describe an unexpected change or event. Commonly used in storytelling or descriptions of surprising moments. Avoid in very formal contexts.

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All of a sudden
Immediately
Suddenly

Frequently asked questions: All of a sudden vs Immediately vs Rapidly vs Suddenly

What's the difference between All of a sudden, Immediately, Rapidly, and Suddenly?

All of a sudden: Unexpectedly or very quickly. Immediately: right away, without waiting Rapidly: quickly or fast Suddenly: Happening quickly and without warning

Which is more advanced: All of a sudden, Immediately, Rapidly, and Suddenly?

Rapidly is the highest level, at B2, on the CEFR scale.

Can you show an example of each?

All of a sudden: All of a sudden, it started to rain heavily. Immediately: He answered the question immediately after it was asked. Rapidly: to **increase/spread/expand rapidly** Suddenly: I **suddenly realized** what I had to do.

Can I use All of a sudden, Immediately, Rapidly, and Suddenly interchangeably?

Not always. All of a sudden, Immediately, Rapidly, and Suddenly 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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