Formal vs Informal Language

You already know that you talk one way with your friends and another way with your teacher. That difference has a name: formal language and informal language. In this lesson, you will learn to spot the clues that tell you which style you are looking at, and you will practice choosing the right one depending on who you are writing to and why.

Formal language is the careful, polished style you use in school writing, letters to adults you do not know well, and any situation where you want to sound serious and respectful. Formal language uses complete sentences, full words instead of contractions, and precise vocabulary. Instead of "Hey, what's up?" a formal greeting might be "Dear Mr. Alvarez," and instead of "a ton of homework" you might write "a large amount of homework."

Informal language is the relaxed style you use with friends, family, and people you know well. It includes contractions like "can't" and "won't," slang words like "cool" or "awesome," and casual greetings like "Hi!" or "Hey there!" Informal language is not wrong, it is simply meant for casual, everyday situations rather than school or professional writing.

Before you write, ask yourself two questions: who is my audience, and what is my purpose? If you are writing a text to a friend, informal language fits perfectly. If you are writing an email to a teacher, a scholarship application, or an assignment for class, you need formal language to sound respectful and clear.

Purpose matters just as much as audience. A birthday card to your cousin can be informal and fun. A letter requesting information from a librarian should be formal, even if you know the librarian well, because the purpose is official. This kind of decision making connects to formal language in writing, where you learn to keep that formal choice consistent across a whole piece.

Look at how the same idea changes depending on the style:

Informal: "Hey Ms. Chen, can I get more time on the project? Thanks!"

Formal: "Dear Ms. Chen, I am writing to request additional time on the project. Thank you for considering my request."

Notice how the formal version avoids contractions, uses a full greeting and closing, and chooses precise words instead of casual ones. Understanding this shift also helps you with formal language and tone, since tone changes along with word choice.

Formal Language: A careful, respectful style of writing or speaking used in school, business, and official situations.

Informal Language: A relaxed, everyday style used with friends and family, often including contractions and slang.

Contraction: A shortened word formed by combining two words, such as "don't" for "do not."

Slang: Casual words or phrases, like "cool" or "awesome," that are common in conversation but avoided in formal writing.

Audience: The person or people who will read or hear your message, which affects how formal or informal you should be.

Purpose: Your reason for writing, such as to inform, to request, or to entertain, which also affects your word choice.

Try sorting a list of words into two columns, formal and informal. Then take an informal message, such as a text to a friend, and rewrite it as a formal email to a teacher. Check your rewrite for contractions, slang, and a proper greeting and closing. This kind of practice builds the habit of noticing your audience and purpose before you write a single word.

Related lessons

• Using Formal Language