formal vs informal english

Formal Versus Informal English: 6 Key Differences

Like many languages, English has a formal and informal register (how a language is used in different situations).

Knowing the differences between the two can significantly improve your level of fluency.

So how do you, say, talk to a superior versus a close family member in English?

We cover all that (and more) in the post below!


Formal Versus Informal English: Definitions and Differences

  • Formal English is the standard and polished form of English used in academic, business and similar contexts (like communications from the government, for example). You use it for people in a higher position than you (like your teacher or boss) or complete strangers—as well as academic or business writing, interviews and presentations.
  • Informal English is used in everyday conversations and written communication in places like social media. You use it with family members, friends and peers (people who are your social equals) in casual settings. 

Here are some formal English phrases you can use and their informal counterparts:

As you can see from the video, formal English uses correct grammar and vocabulary appropriate for the context. Meanwhile, informal English uses contractions, colloquialisms, slang and the like.  

In case you’re wondering what “contractions,” “colloquialisms” and “slang” are, you’re in luck: that’s what we’ll cover in the next sections!


Contractions are common in informal language. Usually, they are two words merged together and are characterized (differentiated from others) by an apostrophe ( ‘ ). 

Here are some of the most common contractions in the English language.

Informal/Contracted FormFormal Form
don'tdo not
shouldn'tshould not
couldn'tcould not
won'twill not
isn'tis not
aren'tare not
didn'tdid not
hasn'thas not
haven'thave not
he's/she'she is/she is
they'rethey are
it'sit is
it'llit will
it'dit would

Phrasal Verbs

A phrasal verb is an idiomatic phrase that consists of a verb and another element, typically an adverb or preposition. Phrasal verbs are more common in informal contexts than formal ones.

Here are some examples:

Phrasal VerbDefinitionExample Sentence
speak upspeak more loudlyI couldn't hear what he said, so I asked him to speak up.
turn downrefuseI can't turn down an invitation from my boss.
find outdiscoverIf my parents find out what I did, they won't be happy.
got awayescapeHe left the door open, and one of the hamsters got away.
run intoto meet suddenlyI didn't expect to run into my friend at the mall, but I did.
set offbegin a journey, startBilbo Baggins set off for his journey into the kingdom of Erebor.
break upend a relationshipThey had such a good relationship that I didn't expect them to break up.
check (somebody/something) outlook at them/it closelyCheck out that new restaurant down the block!
give upquit, surrenderI will never give up on my dreams.
look aftertake care of, watch overHe looks after his nephew while his brother is at work.
put offpostpone, delayThe meeting was put off until next Thursday.
work outfind a solutionI will try to work something out to solve our budget problems.
come acrossappearHe comes across as quiet, but he actually likes to laugh out loud.
bring upmention, introduce a topicYou should bring up that idea in our next meeting. It sounds great!
get alonghave a good relationshipWe live in the same house, so we should all get along.

Colloquialisms and Slang

Colloquialisms and slang are words and phrases regarded as very informal and rarely used in written speech. They typically vary between groups of people, regions, professions or age groups. 

In the English-speaking world, Americans use different slang from Brits (slang word for people from Britain) and Aussies (slang word for people from Australia), such as:

Colloquialism/SlangDefinitionExample Sentence
dudefriend (usually male)Dude, what is happening to you?
buckAmerican dollarHow many bucks do you have left?
zonkedtired, exhaustedWorking 16 hours a day for five days straight left me zonked.
chill outrelaxYou should chill out after working 16 hours a day for five days straight.
sweetgood, awesomeSweet, thank you for the birthday present!
bailleave/depart quicklyI need to bail; the bus is leaving in five minutes.
hellavery, extremelyThe sushi from that new restaurant was hella good.
freak outbecome agitated/anxiousMy friend doesn't freak out even under pressure.
hang outspend time together casuallyDo you want to hang out sometime?
kiddoinformal term of endearment for a child or younger personKiddo, trust me: I know what it's like to be in your position.
no biggieno big deal, not a significant issueNo biggie if you can't come tomorrow. I'm also free next week!
y'allcontraction of "you all"Y'all won't believe what just happened to me!
sickamazing, awesomeDude, that rock concert was sick!
lottacontraction of "lot of"My favorite Led Zeppelin song is "A Whole Lotta Love."
dunnocontraction of "don't know"I dunno where Anne went.


To paraphrase (explain in my own words) the definition from the Merriam-Webster dictionary, an idiom is an expression in which you can’t easily guess the actual meaning from the words used.  

Here are examples of idioms commonly found in informal conversations:

IdiomDefinitionExample Sentence
take a rain checkpolitely refusing an offerSorry, I'll have to take a rain check regarding tonight's dinner.
get the cold shoulderto be treated in an unfriendly wayPlease don't give me the cold shoulder. Talk to me.
spill the beansto reveal a secretCome on. Spill the beans about what's really going on with Lucy.
go Dutchto pay for one's own food or drinkI don't have enough money, so you guys will have to go Dutch for tonight's dinner.
a piece of cakeeasy, effortlessShe's a smart girl, so most school subjects are a piece of cake for her.
break the iceto start a conversationSince we're all new here, let's break the ice!
on the same pageto have the same understanding about a matterI want to make sure we're all on the same page regarding this project.
cut to the chaseget to the point, skip unnecessary detailsIt's better to cut to the chase than to talk on and on without getting anywhere.
cry over spilled milkto get sad or upset about a mistake that cannot be reversedThere's no use crying over spilled milk.
blessing in disguisesomething that looks negative but has a positive outcomeMissing the bus was a blessing in disguise because I met the love of my life at the bus stop.
take it with a grain of saltto not believe something completelyJohn is a liar, so take anything he says with a grain of salt.
break a leggood luckBreak a leg at tomorrow's competition!
needle in a haystacksomething that is hard to findLooking for a ring that fell into the ocean is like looking for a needle in a haystack.
under the weathersickSorry I can't come to the party tonight. I'm feeling under the weather.
kill two birds with one stoneto accomplish two things at the same timeTalking a walk helps me relax and enjoy nature—killing two birds with one stone.

First-person Pronouns

In informal contexts, first-person pronouns (I and we) are more frequently used—this makes for sentences that use the active voice. On the other hand, you’ll typically see passive voice in formal settings, particularly in official or academic writing. 

Here are examples of sentences using first-person pronouns, along with their more formal versions. Notice how different they come across, even though they say the same thing!

Active Voice/Informal FormPassive Voice/Formal Form
We asked the students to complete a survey.The students were asked to complete a survey.
I need to finish this report by Friday night.The report must be finished by Friday night.
We need to write a letter to the supervisor.A letter must be written to the supervisor.
We will give incentives to those who have exceptional performance.Those who have exceptional performance will be given incentives.
I will send you the draft next week.The draft will be sent next week.
We will launch a new product within the next six months.A new product will be launched within the next six months.
I will create a report for the board of directors.A report will be created for the board of directors.
We will fill out these forms and send them to HR.These forms will be filled out and sent to HR.
I will change your order to a different one.This order will be changed to a different one.
I appreciate your thoughts on the matter.Your thoughts on the matter are appreciated.
We will hold the meeting on Wednesday.The meeting will be held on Wednesday.

Everyday Phrases in Formal and Informal English

If you want more examples (and need some handy phrases you can use for friends versus your boss), here’s another table for you!0

And if you want to see these phrases in action, you can browse any of the videos from FluentU‘s library.

FluentU takes authentic videos—like music videos, movie trailers, news and inspiring talks—and turns them into personalized language learning lessons.

You can try FluentU for free for 2 weeks. Check out the website or download the iOS app or Android app.

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Learning the differences between formal and informal English will go a long way in improving your grasp of the language. The better you master words and phrases from both registers, the more natural your speech will sound and the more confident you’ll feel!  

And One More Thing...

If you like learning English through movies and online media, you should also check out FluentU. FluentU lets you learn English from popular talk shows, catchy music videos and funny commercials, as you can see here:


If you want to watch it, the FluentU app has probably got it.

The FluentU app and website makes it really easy to watch English videos. There are captions that are interactive. That means you can tap on any word to see an image, definition, and useful examples.


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For example, when you tap on the word "searching," you see this:


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Start using the FluentU website on your computer or tablet or, better yet, download the FluentU app from the iTunes or Google Play store. Click here to take advantage of our current sale! (Expires at the end of this month.)

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