Formal & Informal Language
Understand register, context, and audience — and know how to adjust your language to suit any situation.
What is Register?
Register refers to the level of formality in your language — how you adjust your vocabulary, grammar, and tone to suit a particular context, audience, and purpose. You already switch register naturally: you speak differently to your teacher than you do to your best friend.
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Formal Register
Used in academic essays, job applications, official letters, and speeches. Precise, impersonal, and professional.
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Semi-Formal Register
Used in emails to teachers, student councils, or workplace contexts. Polite but not stiff.
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Informal Register
Used with friends and family. Includes slang, contractions, and casual sentence structures.
Comparing Formal and Informal Features
| Feature | Formal | Informal |
|---|---|---|
| Contractions | Avoided ("I am", "do not") | Common ("I'm", "don't") |
| Vocabulary | Precise, sophisticated | Casual, slang, colloquial |
| Sentences | Complex, complete | Fragments OK, shorter |
| Pronouns | Often impersonal ("one", "the student") | Personal ("I", "you", "we") |
| Tone | Objective, measured | Expressive, humorous, emotional |
| Example | "I would like to respectfully request..." | "Can you please help me out?" |
Context and Audience
Choosing the right register depends on three factors: who you are writing to, what you are writing about, and where it will appear. Using the wrong register can make you seem disrespectful (too informal) or cold and robotic (too formal).
Scenario 1
Emailing your science teacher about an assignment
Register: Semi-formal — polite but not overly stiff. Use "Dear Mr/Ms [Name]", clear sentences, no slang.
Scenario 2
Applying for a part-time job
Register: Formal — professional vocabulary, no contractions, structured letter format.
Scenario 3
Group chat with classmates
Register: Informal — abbreviations, slang, and emoji are all appropriate here.
Scenario 4
Writing a persuasive essay for class
Register: Formal — academic vocabulary, no first person ("I think"), evidence-based argument.
Common Register Errors
Using "I reckon" in a formal essay
Replace with: "It can be argued that..." or "Evidence suggests that..."
Writing "gonna" or "wanna" in any school task
Replace with: "going to" and "want to" — even in semi-formal contexts.
Beginning a sentence with "So..." or "And..." in a formal essay
Reserve these for spoken or informal written contexts. Use "Therefore," "Furthermore," or "In addition," instead.
Key Vocabulary
Register
The level of formality in language, adjusted to suit the context, audience, and purpose of communication.
Colloquial Language
Everyday, conversational language including slang and informal expressions — appropriate for spoken and informal written contexts.
Contraction
A shortened form of a word or phrase using an apostrophe (e.g., "it's", "don't", "I've") — generally avoided in formal writing.
Tone
The attitude conveyed by the writer through their choice of words, which can be formal, casual, serious, humorous, respectful, etc.
Worked Examples
Rewrite this informal message as a formal email to a teacher.
"Hey, I can't come in tomorrow cause I've got a thing on. Can you send me whatever we do in class? Cheers"
Formal version:
"Dear Mr/Ms [Name], I am writing to inform you that I will be absent from class tomorrow, [Date], due to a prior commitment. I would greatly appreciate it if you could provide me with any materials or tasks covered during that session. Thank you for your time. Kind regards, [Student Name]"
Identify the register error: "In my essay, I reckon that social media is really bad for kids."
Errors: "I reckon" (colloquial, informal), "really bad" (vague and informal), and "kids" (informal — use "children" or "young people" in formal writing).
Formal version: "This essay will argue that unrestricted social media use has a detrimental effect on the wellbeing of young people."
Choose the correct register for this scenario: A letter to the editor of a newspaper.
Register needed: Formal — this is a public document addressed to a professional publication and its readers.
Key features: "Dear Editor", precise vocabulary, no contractions, structured argument, no slang, third-person where possible.
Example opening: "Dear Editor, I write in response to your article of 28 February regarding proposed changes to school hours in New South Wales..."
Knowledge Check
Select the best answer for each question.
Question 1
What does "register" mean in English?
Question 2
Which of the following is appropriate in a formal essay?
Question 3
Which context requires the most formal register?
Question 4
In formal writing, contractions like "don't" and "it's" should be:
Question 5
"Kids these days are kinda addicted to their phones." To make this formal, which version is best?
Key Concepts Summary
- ●Register is the level of formality you use, adjusted for context, audience, and purpose.
- ●Formal writing avoids contractions, slang, colloquial expressions, and first person "I think".
- ●Informal writing uses contractions, casual vocabulary, and a personal tone — appropriate between friends or in creative contexts.
- ●Always consider who will read your text, what the purpose is, and where it will appear before choosing your register.
- ●Using the wrong register can undermine your credibility — a job application in slang or a text to a friend in legal language both create the wrong impression.