Formal, Informal and Slang: Choosing the Right Register for Your Words

The same idea can be expressed in many ways, depending on who's listening and how formal the situation is. Choosing the right word for the situation is called choosing the right register, and it matters as much as spelling.

Three broad levels

Formal: used in official writing, academic work, business letters and serious speeches.

Neutral: the everyday default, appropriate almost anywhere.

Informal and slang: used with friends, family and in casual settings.

A word ladder

Formal	Neutral	Informal
purchase	buy	pick up
commence	begin	kick off
assist	help	give a hand
inquire	ask	check
residence	home	place
children	kids	little ones
depart	leave	head off
terminate	end	wrap up
require	need	gotta have
obtain	get	grab

Using "commence" in a text to a friend, or "kick off" in a legal contract, would sound out of place.

Why register matters

• Job applications and business emails usually call for neutral to formal language.
• Academic essays favour formal vocabulary and structure.
• Texts and social media favour informal language.
• Speaking to elders or strangers often calls for slightly more formal choices.

Getting register wrong can seem cold, pompous, rude or unprofessional.

What slang is

Slang consists of very informal words or meanings used by particular groups, often young people or subcultures. It's lively, creative and often short-lived. Terms that seem cool today can sound dated within a few years, and some fade entirely. Slang varies by region, age group and community.

Cautions with slang

• It can be misunderstood by people outside the group.
• It can seem unprofessional in formal contexts.
• Some slang is offensive, so be careful with words you've only heard online.
• Using slang badly can sound like trying too hard.

Other labels dictionaries use

• Informal / colloquial: used in casual speech.
• Formal: used in serious writing or speech.
• Literary: used mainly in poetry and novels.
• Archaic / obsolete: no longer used, or used only for effect.
• Dated: old-fashioned.
• Offensive / derogatory: insulting.
• Regional (British, US, Australian): typical of a place.
• Technical: used in a specialist field.

Use the labels

Look for these labels in dictionary entries. If a word is marked "informal", think twice before using it in a job application.

Match tone to purpose

Ask three questions before choosing a word:

1. Who's the audience?
2. What's the situation?
3. What impression do I want to make?

Moving between registers

Good communicators shift smoothly: chatting casually with friends, then writing formally at work. It's a skill you can practise by rewriting a message at different levels of formality.

Avoid over-formality

Using long, formal words for their own sake can make writing stiff. Plain, precise language is often more effective.

Practice

Take a text message you've sent, and rewrite it as a formal email. Then do the reverse with a formal sentence. Check unfamiliar words in a dictionary for their register.

Check usage labels and meanings with English Dictionary →