Grammar for Teachers
Grammar for Teachers
🟡 Intermediate

Punctuation: The Comma — Advanced Uses

What this session covers

The most fundamental comma uses — lists, introductory phrases, and coordinating conjunctions — were covered in Lesson 2. This lesson covers the more nuanced uses that appear in formal and academic writing and that change meaning when applied incorrectly. These advanced uses share one common logic: commas around parenthetical information signal to the reader that this material is supplementary and could be removed. Understanding this logic makes all the advanced comma rules clear and memorable.

Personal Reflection

Before you start — think honestly about your own teaching and experience.

Q1
How confident do you feel applying commas around non-defining relative clauses and parenthetical phrases — and explaining the meaning difference the comma makes?
Q2
Which of these have you seen in your students? (Select all that apply)

Discover the Pattern

Look at the examples. Answer each question before reading the explanation — this is how your students will learn too.

1

Read these sentence pairs. Each pair looks almost identical — the only difference is the comma. What meaning change does the comma create?

A. Teachers who work hard deserve more recognition.
B. Teachers, who work hard, deserve more recognition.
A. The students who missed the class will need to catch up.
B. The students, who missed the class, will need to catch up.
Do sentences A and B in each pair refer to the same group of people?

PAIR 1: Sentence A (no commas): 'Teachers who work hard' — the relative clause identifies WHICH teachers deserve recognition. Only the hard-working ones. (Implication: some teachers do not work hard.) This is a defining clause — it restricts the group. Sentence B (commas): 'Teachers, who work hard,' — the commas signal that 'who work hard' is extra information. It implies that ALL teachers work hard and ALL deserve recognition. The commas say: this clause is supplementary information about a group already completely identified. PAIR 2: Sentence A: only the students who missed the class need to catch up — a subset. Sentence B: ALL the students missed the class, and ALL need to catch up. The comma is not just punctuation — it changes what the sentence means. This is the most important lesson about advanced comma use: commas around a relative clause are a meaning signal, not an optional stylistic choice.'

2

Now look at parenthetical phrases — words and phrases inserted into a sentence as asides. Can you find the pattern?

The results, as we had hoped, showed significant improvement.
She is, of course, the most experienced teacher in the department.
The policy, however, has met with considerable resistance.
This approach, I believe, works best with younger learners.
The school, built in 1965, has educated thousands of students.
In each sentence — what could you remove? What do the commas signal about that material?

In each sentence, the material between the commas can be removed without destroying the main sentence: 'The results showed significant improvement.' 'She is the most experienced teacher.' 'The policy has met with considerable resistance.' 'This approach works best with younger learners.' 'The school has educated thousands of students.' The commas signal: this material is supplementary — an aside, a comment, an additional description. The writer is inserting it without making it part of the main flow. TEST: remove the phrase. Is the main sentence still complete and clear? If YES → the material is parenthetical → commas needed. If NO → the material is essential → no commas. This test applies to ALL advanced comma decisions.'

3

Now look at these special uses of the comma. What is being set off by commas in each case?

Tell me, Maria, what you think about the new timetable.
Come in, please.
Sit down, everyone.
Dr Osei, the school's principal, announced the results.
Her first published book, a collection of teaching stories, sold widely.
She was born in Kampala, Uganda, in 1978.
What type of element is being set off in each case?

DIRECT ADDRESS (VOCATIVE): when someone is named or addressed directly within a sentence, their name is set off by commas. 'Tell me, Maria, what you think.' Without the comma, 'Tell me Maria' could be read as 'Tell Maria' — ambiguous. 'Come in, please' and 'Sit down, everyone' — 'please' and 'everyone' function as soft vocative additions, also set off by commas. APPOSITION: a phrase that renames or reidentifies the noun immediately before it. 'Dr Osei, the school's principal' — 'the school's principal' renames Dr Osei. 'Her first published book, a collection of teaching stories' — 'a collection of teaching stories' renames the book. Both can be removed: 'Dr Osei announced the results.' 'Her first published book sold widely.' Commas on both sides. LOCATION REFERENCE: 'Kampala, Uganda' — city followed by country or region, set off by commas in a sentence.'

The Pattern — What You Just Discovered

Advanced comma uses share a common principle: commas set off supplementary, interruptive, or parenthetical material — information that could be removed without changing the core sentence or its meaning. Key uses: non-defining relative clauses (meaning-changing), parenthetical phrases, mid-sentence interrupters, direct address, and appositives. The removal test applies to all.
Special Rule / Notes

THE REMOVAL TEST — the most useful strategy for all advanced comma decisions:

When unsure whether to put commas around a phrase:
(1) Remove the phrase.
(2) Ask: is the sentence still complete? Still clearly identifying the same person/thing?

If YES → the phrase is supplementary (parenthetical) → commas needed.
If NO → the phrase is essential (defining or restrictive) → no commas.

'The headteacher[,] who joined last year[,] has made a big difference.'
→ Remove 'who joined last year': 'The headteacher has made a big difference.' Still clear (one specific person). → Commas needed.
'The teacher who joined last year has made a big difference.'
→ Remove 'who joined last year': 'The teacher has made a big difference.' Now unclear — which teacher? → No commas (defining — essential for identification).

THE MEANING CHANGE — the most important thing to teach:
'Students who practise regularly improve fastest.' (only the practising students — not all students)
'Students, who practise regularly, improve fastest.' (claim about all students — they all practise and all improve fastest)
This is not a stylistic choice. The comma changes the meaning.

HOWEVER — front vs. mid-sentence:
Front: 'However, the results have improved.' (one comma after 'however')
Mid-sentence: 'The results, however, have improved.' (commas before AND after 'however')
Same applies to: therefore, nevertheless, of course, in fact, I think, I believe, it seems.

🎥

Can this phrase be removed without changing the core sentence or losing identification of which noun? YES → commas needed. NO → no commas. Is 'however' / 'of course' / 'I believe' in the middle of the sentence? → commas on both sides. Is someone's name or title used to address them directly? → commas around the name. Is a phrase renaming the noun before it (appositive)? → commas on both sides.

Common Student Errors

All the teachers who are committed deserve support. (when meaning ALL teachers deserve support)
All the teachers, who are committed, deserve support.
WhyIf ALL teachers are being claimed to be committed and ALL deserve support, 'who are committed' is non-defining — extra information. Commas needed. Without commas, the sentence means only the committed subset deserves support.
The report however shows significant improvement.
The report, however, shows significant improvement.
Why'However' mid-sentence as an interrupter needs commas on BOTH sides. 'The report, however, shows...' Without both commas, the sentence is harder to parse.
Please everyone listen carefully to the instructions.
Please, everyone, listen carefully to the instructions.
Why'Everyone' is a direct address (vocative). Commas set off the term of address: 'Please, everyone, listen...' Both commas needed to clearly mark the address.
The school founded in 1965 has educated thousands of students.
The school, founded in 1965, has educated thousands of students.
Why'Founded in 1965' is a participial phrase — additional information about 'the school', which is already identified. Remove it: 'The school has educated thousands of students.' Still complete → commas needed.
She was born in Kampala Uganda and moved to Lagos in 2005.
She was born in Kampala, Uganda, and moved to Lagos in 2005.
WhyIn location references, a comma follows the city name ('Kampala,') and a comma follows the country name when more follows ('Uganda,').

Check Your Understanding — Part 1

Decide where commas are needed in each sentence. Think about whether the phrase is essential (defining — no commas) or supplementary (non-defining / parenthetical — commas needed).

The school which was built in 1965 has recently been renovated.___________
The results I believe show a significant improvement in student literacy.___________
Tell me James have you completed your report yet?___________
Dr Osei the school's principal announced the results at the assembly.___________
Students who study regularly are much more likely to succeed.___________
0 / 5 answered

Check Your Understanding — Part 2: Why Is It Wrong?

Each sentence has a comma error. Write the correct version and explain why — then reveal the answer.

The headteacher who joined last September has already made several positive changes.
Write the correct sentence:
Explain why it is wrong:
The headteacher, who joined last September, has already made several positive changes. (if there is one headteacher — non-defining)
In most contexts, 'the headteacher' refers to one specific person — already fully identified by the article 'the'. 'Who joined last September' adds extra information about this already-identified person. It is non-defining → commas needed. Remove it: 'The headteacher has already made several positive changes.' Still complete and clear.
The policy however does not address the most fundamental issues.
Write the correct sentence:
Explain why it is wrong:
The policy, however, does not address the most fundamental issues.
'However' mid-sentence as an interrupter requires commas on BOTH sides: 'The policy, however, does not...' Without both commas, the sentence is harder to parse and the interrupter is not clearly marked.
Her second report a detailed study of rural schools was well received by educators.
Write the correct sentence:
Explain why it is wrong:
Her second report, a detailed study of rural schools, was well received by educators.
'A detailed study of rural schools' is an appositive — it renames 'her second report'. Appositives take commas on both sides. Remove it: 'Her second report was well received.' Still complete. Commas needed on both sides.
She was born in Accra Ghana and later moved to Lagos Nigeria.
Write the correct sentence:
Explain why it is wrong:
She was born in Accra, Ghana, and later moved to Lagos, Nigeria.
In location references, a comma follows the city name and a comma follows the country name when more information follows: 'Accra, Ghana,' and 'Lagos, Nigeria.' This prevents the reader from running city and country names together ambiguously.

Classroom Teaching Sequence

Use this sequence directly in class — guided discovery, no textbook needed. Tap each step to mark it done.

0 / 5 done
1

STEP 1 — THE MEANING CHANGE (8 minutes): Write on the board:
'Teachers who work hard deserve recognition.'
'Teachers, who work hard, deserve recognition.'
Ask: do they mean the same thing? Give pairs two minutes. Elicit the distinction. Establish: the comma signals non-defining (all teachers). No comma signals defining (only the hard-working ones). This is the most important conceptual point in the lesson.

2

STEP 2 — THE REMOVAL TEST (8 minutes): Teach the removal test explicitly:
(1) Remove the phrase in question. (2) Is the sentence still complete and clearly identifying the same noun? YES → commas (non-defining/parenthetical). NO → no commas (defining/essential).
Apply to five examples together. Students explain their decision each time.

3

STEP 3 — INTERRUPTERS (5 minutes): Teach that 'however', 'of course', 'I believe' and similar used mid-sentence take commas on BOTH sides. Contrast with front-of-sentence position (comma after only). Drill with five sentences.

4

STEP 4 — DIRECT ADDRESS AND APPOSITION (5 minutes): Teach direct address (name + commas when addressing someone) and apposition (renaming phrase + commas on both sides). Students produce two examples of each.

5

STEP 5 — REVISION ACTIVITY (5 minutes): Give students a short formal paragraph with all advanced commas removed. Students add them in the correct positions. Compare and discuss each addition.

Ready-to-Use Classroom Materials

Use directly in class — copy, adapt, or read aloud. No printing needed.

1 The Removal Test — Pair Activity (No materials)
Read each sentence. Students apply the removal test to the bracketed phrase: remove it, ask 'Is the sentence still complete and clearly identifying the same noun?' YES → commas needed. NO → no commas. Students justify each decision.
Example sentences
The students [who missed the first week] will need extra support. → Remove: 'The students will need extra support.' Yes — but which students? Lost. → NO (defining, no commas)
Mr Osei [the school's deputy principal] will chair the meeting. → Remove: 'Mr Osei will chair the meeting.' YES — still clear. → Commas needed (appositive)
The school [which opened in 2001] has 800 students. → Remove: 'The school has 800 students.' YES — still clear. → Commas needed (non-defining)
A school [that has strong leadership] tends to perform well. → Remove: 'A school tends to perform well.' YES but the defining restriction is lost — it becomes a claim about all schools. → NO (defining)
2 Add the Commas — Formal Report Passage (No materials)
Dictate this passage without the advanced commas. Students add commas in the correct positions. Go through the answers together, naming the rule for each comma.
Example sentences
Passage to dictate:
'The school's annual report which was published last month outlines significant progress. The headteacher Dr Aminata Diallo noted that results as expected had improved across all subjects. The English department however still faces challenges with class sizes. This problem it seems will require additional resources. The school founded in 1972 remains one of the most respected institutions in the region.'
Corrected:
'The school's annual report, which was published last month, outlines significant progress. The headteacher, Dr Aminata Diallo, noted that results, as expected, had improved across all subjects. The English department, however, still faces challenges with class sizes. This problem, it seems, will require additional resources. The school, founded in 1972, remains one of the most respected institutions in the region.'
3 Error Hunt — Dictation (No materials)
Dictate these sentences. Students find and correct comma errors. Some sentences are correct. Name the error type and explain the rule.
Example sentences
The report, which was submitted on time, received full marks. ✓ (non-defining — correct)
The teacher who submitted on time received full marks. ✓ (defining — correct)
The results however have shown improvement. ✗ → The results, however, have shown improvement.
Tell me James what you think. ✗ → Tell me, James, what you think.
She was born in Accra Ghana and later moved to Lagos. ✗ → Accra, Ghana,

Plan Your Next Steps

For each strategy, choose the option that best describes where you are now.

Teach the removal test as the primary decision strategy — it works for all advanced comma situations
The meaning difference between defining and non-defining is the most important conceptual lesson — return to it regularly when students write relative clauses
Use formal report writing as the context for practising advanced comma use — it is the most natural environment for these patterns
Lesson 7 covers the semicolon and colon — punctuation marks that are closely related to the comma's joining and separating functions
What is the one change you will make next time you teach this grammar point?

Key Takeaways

1 Non-defining relative clauses (extra info about an already-identified noun) → commas on both sides. Defining clauses (identifying which one) → no commas. The comma changes the meaning
2 Removal test: remove the phrase. If the sentence is still complete and clearly identifies the same noun → commas needed. If not → no commas
3 Interrupters mid-sentence ('however', 'of course', 'I believe') → commas on BOTH sides. At the front of a sentence → comma after only
4 Direct address (vocative): name or title used to address someone → commas on both sides: 'Tell me, Maria, what you think'
5 Appositives (phrases that rename the noun before them) → commas on both sides: 'Dr Osei, the principal, announced...'