Formal vs Informal English
B1 · IntermediateRegister & StylePurchase vs buy. I would like to inform you vs Just so you know. Same meaning, different register.
What you'll learn
- Formal English favors longer, often Latinate vocabulary (purchase, commence, assistance); informal English favors everyday words and phrasal verbs (buy, start, help)
- Formal writing usually avoids contractions (do not, cannot) in favor of full forms; informal English uses contractions freely (don't, can't)
- Formal English uses more passive voice and impersonal structures; informal English favors direct, personal, active sentences
- Formal letters/emails use set opening and closing conventions (Dear Sir or Madam, Yours faithfully); informal ones are much more flexible (Hi, Best)
- Register should stay consistent across a whole message — mixing very formal and very informal language in the same text can sound odd, even if each word is used correctly
Same meaning, different register
Formal and informal English often say the same thing in completely different words. Neither one is more 'correct' grammatically — the right choice depends on the situation: who you're talking to, and how official or personal the context is.
Formal vocabulary vs everyday words
Formal English often reaches for a longer, more Latinate word where informal English uses a short, everyday one or a phrasal verb: purchase/buy, commence/start, assistance/help, obtain/get, sort out/resolve, find out/determine.
Contractions, passive voice, and structure
Formal writing tends to avoid contractions, favor the passive voice for an impersonal, official tone, and use fuller, more complex sentences. Informal English uses contractions freely and favors direct, active, personal sentences.
Formal and informal conventions
Letters and emails follow set conventions depending on register: a formal letter to an unknown recipient opens with 'Dear Sir or Madam,' and closes with 'Yours faithfully,'; an informal message might simply open with 'Hi,' and close with 'Best,' or 'Thanks,'.
Watch out
A business email to someone you don't know well should avoid contractions, casual greetings like 'Hey,' and informal phrasing like 'just wanted to'.
Overly formal vocabulary in a casual text or conversation with friends sounds stiff and unnatural, even though it's grammatically correct.
Register should stay consistent throughout a text — a formal opening followed by informal vocabulary ('gotta', 'super') reads as inconsistent, not friendly.
Real life — The same request, two ways
"Dear Ms. Carter, I am writing to request a copy of last month's invoice. I would appreciate your prompt attention to this matter."
"Hey, could you send me last month's invoice when you get a sec? Thanks!"
Practice
Exercise 1 · Choose the more formal word
Which word is more FORMAL?
Exercise 2 · Choose the more informal word
Which word is more INFORMAL?
Exercise 3 · Choose the appropriate sentence
Which sentence is more appropriate in a formal business email?
Exercise 4 · Choose the more formal sentence
Which is more typical of FORMAL written English?
Exercise 5 · Choose the correct formal rewrite
'I can't make it to the meeting.' Rewritten more formally, this becomes...
Exercise 6 · Choose the correct formal closing
Which closing is appropriate for a FORMAL letter to someone whose name you don't know?
Exercise 7 · Choose the correct description
Contractions (don't, can't, it's) are...
Exercise 8 · Choose the formal equivalent
'Sort out' (informal phrasal verb) has a more formal single-word equivalent:
Exercise 9 · Rewrite more formally
Rewrite more formally: 'I gotta go now.'
Exercise 10 · Rewrite more informally
Rewrite more informally: 'We regret to inform you that your application was unsuccessful.'
Exercise 11 · Sort into groups
0 / 8 sorted
Quick challenge
Five quick questions to check what stuck.
Question 1 / 5
Score: 0/0
Which is more formal?
You learned
- Formal English favors longer, Latinate vocabulary; informal English favors everyday words and phrasal verbs.
- Formal writing avoids contractions; informal English uses them freely.
- Formal English favors passive, impersonal structures; informal English favors direct, active ones.
- Formal and informal letters/emails follow different opening and closing conventions.
- Keep register consistent throughout a text — don't mix formal and informal language in the same message.
Related grammar lessons
Politeness and Softening
Learn how English softens requests, opinions, and bad news through modal remoteness (could/would instead of can/will) and indirect question structures (I was wondering if..., Do you think you could...) — beyond the please/tag softeners already covered for imperatives, and beyond the certainty-hedges used for opinions.
Register and Style
Step back and see the whole picture: register is a continuum from very formal to very informal, not a binary switch, and the markers you've already studied — nominalization, passive voice, contractions, discourse markers, ellipsis — are all signals along that same spectrum. This lesson ties them together and focuses on matching register to audience, purpose, and consistency.
Standard vs Non-Standard English
Learn to recognize widely used non-standard English features — ain't, dialectal subject-verb agreement (they was), irregular-verb leveling (I seen, he done), and 'them' as a demonstrative (them books) — as legitimate, rule-governed features of real dialects and casual speech, not simply mistakes, while understanding why formal writing and exams expect the standard forms instead.
Short Forms and Ellipsis
Learn how casual spoken English drops the subject and/or auxiliary at the start of a sentence — Got it!, Want some?, See you later!, Been waiting long? — a specifically conversational pattern, distinct from the structural ellipsis found in comparisons and after auxiliaries.