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By British Council

11 September 2025 - 15:55

a group of young people looking at a laptop

When you’re learning English, it’s important to be aware that there are two different registers or types to master: formal vs informal English. 

Formal English is used in academic and professional contexts. Informal English is used in more casual environments or with friends and family. 

Using the appropriate register for the context is an important part of communicating effectively in English. It will help you seem more natural and confident in English in different contexts, both in social situations and at work. In fact, using the wrong register is one of the most common mistakes made in the IELTS Writing test.

It can be difficult to know the differences between formal vs informal English. It can also be tricky to adapt your language without affecting your meaning. So let’s take a look at some examples of common challenges in formal vs informal English writing. 

Nine common mistakes in formal vs informal English

There are a number of common mistakes in formal vs informal English. Run through the following checklist and apply it to your own writing. 

1. Avoid contractions

As a rule, contractions should be avoided in formal English writing. They’re fine to use when speaking in academic or professional environments, but when it comes to writing essays, reports, emails and presentations, it’s preferable to use the expanded form. However, you can use contractions if they are part of a direct quote or a common idiom like ‘it’s a no-brainer.’ 

Informal English: 'In the following section of the presentation, I’ll explain the results of the experiment.'
Formal English: 'In the following section of the presentation, I will explain the results of the experiment.'

2. Don’t use slang in a business or academic context

It is never appropriate to use slang in formal contexts like work or university. Try to find more neutral, specific vocabulary to express yourself. 

Informal English: 'The meeting was absolutely bonkers.'
Formal English: 'The meeting was very poorly organised.'

3. Avoid casual greetings via email

Like contractions, casual greetings are generally acceptable in informal, in-person conversations. There’s nothing wrong with meeting your boss at the coffee machine and saying ‘Hey Karen, how’s your morning?’ However, when it comes to the written word, it’s important to be more formal. So, when you start emails, make sure you are using an appropriate greeting. 

Informal English: 'Hey Liz, I need help with a project.'
Formal English: 'Dear Ms. Smith, I am writing to ask for help with a project.'

Top tip: different companies have different cultures. Some workplaces are much less formal than others. If you are unsure how to write, follow the example of others in your office. 

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4. Don’t use non-standard abbreviations

Online English language is full of abbreviations like ‘brb’ (be right back) and ‘ofc’ (of course). It’s fine to use these when you’re DMing (direct messaging) a friend - but these abbreviations are very casual and inappropriate for academic or professional language.

Informal English: 'IDK what the next steps will be on this project.'
Formal English: 'I don’t know what the next steps will be on this project.'

5. Don’t be too direct

English speakers often make requests in an indirect way, especially compared to some other languages. Framing requests as questions, and using ‘please’ and ‘thank you’, sound more professional and polite.  

Informal English: 'Give me the documents by tomorrow.'
Formal English: 'Could you please send me the documents by tomorrow at the latest? Thank you.'

6. Be wary of casual phrasal verbs

Phrasal verbs are essential for proficiency - but not all phrasal verbs are appropriate for academic or professional contexts. For example, phrasal verbs like ‘figure out’ instead of ‘understand’, or ‘call off’ instead of ‘cancel’ are too casual for formal written English. Instead, try to use verbs that clearly express what action is being taken. 

Informal English: 'The organisation will check out this issue next week'
Formal English: 'The company will conduct a review of this issue next week.'

7. Avoid vague nouns or expressions

Vague expressions are a group of words and phrases which are broad, general terms lacking in specific details. Common examples include ‘stuff’, ‘guy’ and expressions like ‘sort of’ and ‘that kind of thing’. They are commonly used in informal English, but when it comes to formal English it’s important to avoid language that is casual and unclear. Instead, make sure you are using words that communicate your meaning clearly. 

Informal English: 'Can you send me that thing we talked about a while ago?'
Formal English: 'Could you please send me the form I mentioned last week?'

8. Don’t be overly formal in casual conversation

Make sure to simplify your language in casual contexts or you might give people the impression that you are unfriendly or distant.

Informal English: 'Would you be so kind as to accompany me to the post office and assist me in sending this parcel?'
Formal English: 'Would you come with me to the post office to help me send this parcel please?'

9. Avoid overarticulate, long responses

Your tone when writing a WhatsApp message to your friend should be different from writing an email to your supervisor. You can be more direct and to the point in an informal conversation with people you know well. 

Informal English:  'Sorry for the late reply—will respond soon'
Formal English: 'Apologies for the delay in my reply. I will get back to you promptly.'

Mastering formal vs informal English

These are just some of the examples and ways to understand formal vs informal English and improve your writing skills. 

Adapting your English to formal and informal situations is a good preparation for IELTS Writing, and it also helps you understand cultural norms in English. So, when you move to an English-speaking country, you’ll be better prepared for formalities like job interviews and filling in official documents, as well as casual socialising and being able to convey your personality in English.

So, what’s next for you? If you’re feeling confident in the difference between formal vs informal English, then you might be ready for your IELTS test: 

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