1. Look at the contractions

No contractions → more formal
Contractions → more informal

  • Formal: We do not agree with this proposal.

  • Informal: We don’t agree with this.

2. Look for phrasal verbs vs single verbs

Single, Latinate verbs → formal
Phrasal verbs → informal

  • Formal: We will investigate the issue.

  • Informal: We will look into the issue.

Common swaps:

  • ask for → request

  • find out → discover

  • put off → postpone

  • fix → resolve

3. Check sentence length and structure

Longer + indirect → formal
Short + direct → informal

  • Formal: We would appreciate your feedback at your earliest convenience.

  • Informal: Please send feedback soon.

4. Look for polite “softeners”

Formal language often uses buffers like:

  • We would like to…

  • We kindly request…

  • We regret to inform you…

  • We appreciate your cooperation…

Informal English often removes them:

  • We need…

  • Please send…

  • Can you explain…

Quick shortcut rule

If the sentence sounds like an email to a client → formal
If it sounds like a message to a colleague → neutral/informal

Mini test

Try asking yourself:
Would I say this in a WhatsApp message?

If yes → informal/neutral
If no → formal