Formal vs Informal English: 7 ESL Activities

Formal vs informal English — also called register — is the difference between “I am writing to inquire about the position” in a job application and “hey, just asking about the job” in a text. ESL learners need to recognize which register a situation demands and produce the right language for it. The seven activities below build that skill through sorting, rewriting, role-play, and real-world text work — not memorized lists.

Here’s a scenario that Taiwanese English teachers will recognize: a student writes a university professor to request an extension and opens with “Hey Professor Chen, so I’m kinda swamped this week…” The vocabulary is accurate, the grammar is clean, but the email lands badly. The student didn’t fail at English — they failed at register. According to a 2022 survey by British Council’s English at Work research, register mismatch is among the top three communication errors professionals make when using English in workplace contexts. It’s a teachable problem, and these activities are designed to fix it.

What Is Register in English?

Register refers to how language shifts depending on who you’re talking to, what the situation demands, and what relationship exists between the speakers. Linguist M.A.K. Halliday described register as determined by three factors: field (what’s being discussed), tenor (the relationship between participants), and mode (spoken, written, or digital). For classroom purposes, three levels cover most situations.

Formal: Written for professional, academic, or official audiences. Complete sentences, no contractions, no slang. “I would like to request a meeting at your earliest convenience.”

Neutral: Appropriate across most contexts. Clear and polite, but not stiff. “I’d like to set up a meeting sometime this week.”

Informal: Natural in conversations with friends or family. Contractions, casual vocabulary, sometimes incomplete sentences. “Can we meet up this week? Need to talk.”

Most ESL textbooks list formal vocabulary substitutions (utilize → use, commence → start) but skip the deeper question: how do students know which register to choose? The activities below build that judgment.

Activity 1: The Register Sort

Print 30 to 40 short phrases on separate cards — a mix of formal, neutral, and informal expressions covering greetings, requests, apologies, and sign-offs. Students work in pairs to sort them into three columns: formal, neutral, informal.

Good examples to include: “Dear Sir or Madam” vs “Hey” vs “Hi there.” “I regret to inform you” vs “I’m sorry to say” vs “bad news, btw.” “I look forward to hearing from you” vs “Hope to hear from you soon” vs “get back to me.”

The sorting discussion is where learning happens. Students will disagree on neutral vs formal, and that disagreement is the point — register isn’t binary, it’s a spectrum. After pairs finish, do a class debrief where each group defends their placements. You’ll surface the conceptual mismatches early, before they show up in written work.

This pairs well with the scaffolding techniques covered here — give lower-level groups a reference list before they start the sort rather than during.

Activity 2: Rewrite the Message

Students get a casual message and must rewrite it in formal English, then take a formal text and make it appropriately casual. The bidirectional transformation is critical — students who can only move one direction haven’t internalized the rules, they’ve memorized a formula.

Source material that works well in Taiwan: LINE messages written in that mixed formal-casual tone common in student-to-teacher communication, customer service chat transcripts, or WhatsApp voice note transcripts. These are real, local, and immediately recognizable.

A sample prompt: Rewrite this LINE message as a formal email to your department head: “Hey sir sorry for late reply!! I had fever but I’m ok now. Can I hand in report on Thursday?? Thank you so much!!!”

Students will instinctively overcorrect in both directions — the formal version becomes stiff and overwrought, the casual version becomes rude. That overcorrection is useful data. Collect common patterns and address them as a class.

Activity 3: Role-Play with Context Cards

Give each pair of students a situation card that specifies the same communicative goal but two different relationships. For example: “Ask someone to reschedule a meeting — Card A: your manager; Card B: your classmate.” Both students plan what they would say, then compare. The content is identical; the language will differ sharply.

Good situation pairs for adult learners:

Apologize for being late — to your boss vs. to a friend
Ask for help with a task — to a senior colleague vs. to a peer
Decline an invitation — to a client vs. to a family member
Request a document — from a government office vs. from a classmate

After each role-play, students identify two or three specific language choices that changed between the formal and informal version. Writing these down prevents the lesson from staying surface-level. This technique connects directly to what makes drama activities effective — giving language a real social context makes it stick.

Activity 4: Analyzing Real-World Texts

Collect three authentic texts on the same topic — a tweet, a news article excerpt, and a paragraph from a company annual report. All three describe the same event or issue. Students compare the texts and identify every place where register is visible: vocabulary choices, sentence length, use of passive vs. active voice, hedging language, and pronoun choices.

For 2026, AI-related content works particularly well because students have personal experience with how differently people discuss AI on Twitter vs. in a CNBC article vs. in a McKinsey report. The topic is consistent, but the language is dramatically different across registers.

A comparison grid helps: students fill in rows for “vocabulary formality,” “sentence structure,” “personal vs. impersonal tone,” and “hedging/certainty.” Filling the grid forces close reading. It’s more useful than open-ended discussion at this stage because it names specific features rather than general impressions.

Activity 5: The Formal Email Makeover

Write a deliberately bad professional email — one that uses the right overall structure (subject, greeting, body, close) but gets register badly wrong throughout. Students identify the problems and rewrite the email. The “find and fix” format is more effective than blank-page drafting because it gives students something to argue against.

Example source email (written for maximum instructional value): “Subject: About the report thing / Hi Managers! Hope you guys are doing good 😊 So I checked out the Q3 numbers and yeah, they’re pretty bad lol. I’m gonna send you my thoughts later but first can you all make time to chat? Like maybe Thursday? Thanks a bunch 🙏”

Students should be asked to identify at least six specific problems before they start rewriting. The identification step forces analysis rather than instinct. After rewriting, pairs swap their versions and evaluate each other against a simple three-point rubric: appropriate greeting, professional vocabulary throughout, appropriate close.

Activity 6: Social Media to Academic Writing

Students take a short social media post — a tweet, an Instagram caption, or a TikTok text overlay — and expand it into a 100-word academic paragraph on the same topic. The constraint forces the most extreme register shift in the sequence.

This works because social media posts strip out hedging, attribution, citation, and complex sentence structures — exactly the features that define academic register. Students who struggle to write formally often don’t lack vocabulary; they lack sentence-level models. Expanding a known idea into an academic form provides the scaffolding.

Source example: A tweet reading “climate getting wild, we kinda need to act now tbh 🌍 #ClimateAction” becomes the prompt. Students must write a paragraph that attributes the concern to a source, uses hedged language (“evidence suggests”), avoids contractions, and includes at least one complex sentence. A quality academic paragraph from this prompt runs to about 80–100 words — achievable, but demanding enough to be meaningful practice. This connects naturally to the information-gap approach where students bring different knowledge to a shared task.

Activity 7: Build a Register Spectrum Wall

Create a class artifact: a long paper strip or whiteboard section divided into five zones from “very formal” to “very casual.” Throughout the unit, students add language items — individual phrases, vocabulary, discourse markers, greeting formulas — to the spectrum. The wall grows as the unit progresses.

The key rule: students must justify placement. “I put ‘I’m reaching out to’ in the formal zone because you’d only write it in an email, not a text” is the kind of metalinguistic reasoning the activity is designed to develop. Items that the class disagrees about stay in a “contested” middle zone and become discussion material for later lessons.

By the end of the unit, the wall becomes a revision tool. It’s also a visible record of collective learning, which matters for motivation in long courses. Students who see 80+ items they’ve analyzed and placed themselves have something to point to.

How to Sequence These Activities

Don’t run all seven activities in the same week. The Register Sort and Text Analysis are recognition activities — use them first, in the first one or two lessons on register. The Rewrite activities and Role-Play work best mid-unit, once students can identify register markers but before they’re producing independently. The Email Makeover and Social Media to Academic writing are production activities that assume the preceding work is in place.

The Register Spectrum Wall runs throughout the unit as an ongoing classroom resource. Start it in the first lesson and add to it in every subsequent session. By the time students reach the production activities, the wall is a scaffold they built themselves — which is more effective than any teacher-created reference sheet.

Register teaching doesn’t end when the unit does. The habits students build here — pausing to identify context, relationship, and purpose before writing or speaking — apply in every language task they face in professional and academic life.

Mga Pinagmumulan

British Council — English at Work: Global Research — Research on English language communication challenges in workplace settings.
Cambridge English — Why Register Matters in ELT — Overview of register’s role in communicative competence.
Halliday, M.A.K. (1978). Language as Social Semiotic: The Social Interpretation of Language and Meaning. Edward Arnold — Foundational theory of register in linguistics.

🇹🇼 Also in Chinese: This topic is available on 18KEnglish.com — bilingual worksheets for Chinese-speaking students.