Letter Writing for NIACL AO 2025: Formal vs Informal Guide

1. Why Knowing Formal vs Informal Matters

Letter writing is a 10-mark component in the NIACL AO 2025 Descriptive English section. Examiners not only check content, but also structure, tone, formatting, and appropriateness. You may be asked to write either a formal or an informal letter. Knowing the differences well helps you choose the right style quickly and avoid penalties.

Latest exam feedback shows that many aspirants lose marks because they:

Mix up tone (formal prompts handled too casually; informal ones too stiff).
Forget correct salutations / closings.
Use incorrect formats (sender/receiver address, subject, etc.).

So getting these details right is essential.

2. Key Differences: Formal vs Informal Letters

Here is a side-by-side comparison of what distinguishes formal from informal letters in the NIACL AO exam context.

Feature	Formal Letter	Informal Letter
Purpose	Official communication: complaints, requests, applications, suggestions to authorities, etc.	Personal communication: writing to family, friends, acquaintances about personal matters, experiences, greetings, etc.
Tone / Language	Polite, impersonal, respectful, professional. Avoid contractions (“can’t”, “don’t”), slang, colloquialisms. Use formal expressions.	Friendly, personal, conversational. Use first person, contractions, colloquial expressions acceptable.
Structure / Format	Must include proper sender’s address, receiver’s address, date, subject line (optional but helps), formal salutation (“Dear Sir/Madam” etc.), body split into introduction, purpose, details, conclusion; proper closing like “Yours faithfully / Yours sincerely” etc.	More flexible: address and date, casual salutation (“Dear [Name]”, “Hi …”), body with personal touches; closing can be warm (“Best wishes”, “Lots of love” etc.). No need for rigid subject line usually.
Content / Style	Stay on topic. Stick to relevant points. Use facts, polite requests or applications. Avoid personal emotional content unless it’s relevant.	More relaxed storytelling, sharing of feelings, non-formal expressions, possibly anecdotes. More personalization.
Length and Word Choice	Medium length, concise, formal vocabulary. Vocabulary and sentence structure should reflect seriousness.	Can be informal in style, shorter or longer depending on the relationship; language lighter.
Ending / Closing	Formal closing, signature (your name), possibly designation.	Casual closing, sign off with your name, possibly informal sign-off phrase.

3. Format & Essential Components of Each Type

Formal Letter Format Checklist

Sender’s address (top left)
Date (just below sender’s address)
Receiver’s address (on left, after a line)
Subject line (one-line summary of purpose, often prefaced with “Subject:”)
Salutation (e.g. “Dear Sir/Madam,” or “Dear Mr./Ms. [Name],”)
Body
- Introduction: reason for writing
- Main content: details, arguments, requests, suggestions
- Conclusion: summarize expectation, express thanks or hope
Closing / Signature (e.g. “Yours faithfully,” or “Yours sincerely,” + your full name)

Informal Letter Format Checklist

Sender’s address and date (similar to formal, but relaxed position accepted)
Salutation (e.g. “Dear Raj,” “Hi Priya,” etc.)
Body
- Friendly opening: greeting, enquiring about the person
- Main content: purpose or stories or news or personal matters
- Closing: warm closing, personal wishes
Ending / Signature (e.g. “Warm regards,” “Lots of love,” “Yours,” etc.)

4. Tips for Writing Letters in NIACL AO 2025 (Both Styles)

Read prompt carefully: check whether it asks for formal or informal style. Don’t guess.
Plan your letter: spend first minute outlining the purpose, main points, what tone to adopt.
Keep language consistent: if writing formally, maintain formal tone throughout; if informal, keep it friendly but clear. Don’t mix styles.
Use appropriate vocabulary: in formal letters use words like “request”, “appreciate”, “concern”, “inconvenience”, “regret”, etc.; in informal, words like “hope”, “miss”, “happy”, etc.
Ensure correct salutations & closings: formal letters often penalised for sloppy closings.
Maintain clarity & brevity: even in informal letters, avoid off-topic digressions. In formal letters especially, avoid repetition.
Proofread: check grammar, punctuation, spelling, sentence flow.

5. Common Mistakes & Observations (2025)

From recent NIACL AO exam–level practices:

Some aspirants write formal letters using contractions (“I’m”, “don’t”) which looks casual.
Others write informal letters but include overly formal phrases, making tone inconsistent.
Missing subject line in formal letters leads to weaker impression.
Not addressing receiver properly: generic “To Whom It May Concern” vs proper designation.
Ending informal letters too abruptly; not enough wrap-up.
Excess information in formal letters (irrelevant points) or insufficient explanation in informal ones.

6. Sample Formal & Informal Letter (Brief Comparison)

Prompt (for both): Write a letter to your supervisor informing them about a delay in project submission due to unavoidable personal reasons.

Formal Letter Sample (extract)

[Your Address]
Date: 10 September 2025
The Supervisor,
XYZ Company,
Mumbai – 400050
Subject: Delay in Submission of Project Report
Dear Sir/Madam,
I am writing to inform you that due to a sudden medical emergency in my family, I will be unable to submit the project report by the scheduled deadline of 15 September. I request a short extension of three days to ensure that the report reflects accurate data and quality analysis. I assure you that I will complete all pending sections and submit by 18 September.
Thank you for your understanding.
Yours faithfully,
[Your Name]

Informal Letter Sample (extract)

[Your Address]
Date: 10 September 2025
Dear Raj,
I hope you’re doing well. I just wanted to let you know that due to some family issues, I won’t be able to finish the project report by 15 September. Would it be okay if I submit it by 18? I promise to make sure I cover everything carefully so you’re satisfied.
Thanks a lot for your patience.
Warm regards,
[Your Name]

7. Practice Plan for Mastering Both Styles

Week	Activity
Week 1	Write 2 formal and 2 informal letters on different topics. Focus on format and tone.
Week 2	Under timed conditions (8-10 mins per letter), practice writing based on mock prompts. Review mistakes.
Week 3	Swap letters with a peer or mentor and get feedback specifically on tone, appropriateness, format.
Week 4	Final polish: write one formal + one informal with perfect format, minimal mistakes, and correct tone.

8. Conclusion

Letter writing plays a crucial role in the NIACL AO 2025 Descriptive English section. Being able to distinguish between formal and informal styles, using the right format, consistent tone, and practicing both kinds diligently will give you a strong edge. Follow the checklists, avoid common pitfalls, and with regular feedback and timed practice, you can maximize your marks in letter writing.