Difficulty: Beginner | Prerequisites: Constructing Sentences notes
Punctuation is how you signal pauses, relationships between ideas, ownership, and quotation in writing. Incorrect punctuation can change meaning entirely ("I love eating, crafts, and pets" vs. "I love eating crafts and pets"). This section covers commas, apostrophes, semicolons, colons, exclamation points, quotation marks, capitalisation, italics, numbers, and abbreviations. These rules apply to every piece of writing you produce.
Commas separate list items, join clauses with conjunctions, and set off introductory phrases. Apostrophes mark contractions and possession (but never possessive pronouns). Semicolons connect closely related independent clauses. Colons introduce lists, quotations, and closely linked ideas. Quotation marks set off dialogue and direct quotations. Exclamation points should be used sparingly. Capitalisation, italics, numbers, and abbreviations each follow specific conventions that vary by style guide.
Comma
A punctuation symbol used in multiple ways to indicate a pause or particular organisation within a sentence.
Apostrophe
A punctuation symbol that indicates possession or is used to form contractions.
Contraction
A word formed by abbreviating or combining other words (e.g., "can't" from "cannot"). The apostrophe replaces the missing letters.
Comma splice
A grammatically incorrect sentence in which a comma alone separates two or more independent clauses.
Semicolon
A punctuation mark that connects two closely related independent clauses into one sentence, or separates complex items in a list.
Colon
A punctuation mark used to introduce lists, quotations, or closely linked ideas after an independent clause, or to separate a title and subtitle.
Quotation marks
Punctuation used to indicate a verbatim account from a source, identify speech in narrative writing, or draw attention to specific words.
Separate three or more items with commas. Place the final comma before "and" or "or" (the Oxford comma): "I'm going to Nashville, Atlanta, and New Orleans."
This also applies when list items are phrases: "My kids need to brush their teeth, gather their backpacks, and eat breakfast before school."
Place the comma before the coordinating conjunction: "The day is cold, but it's not snowing."
When the dependent clause comes first, follow it with a comma: "Since it's not snowing, we can't go skiing." When the independent clause comes first, no comma is needed: "We can't go skiing since it's not snowing."
Set off an introductory phrase with a comma: "On snowy days, it's common for many people to work from home."
Surround interruptions or non-essential clauses: "My friends, who have never skied before, are planning a trip."
Set off dialogue: '"I can't wait to build a snowman," said my sister.'
In dates (January 1, 2016) and geographic names (Minneapolis, Minnesota)
A useful editing trick: read aloud and note where you naturally pause. That is often where a comma belongs. A comma where it does not belong can cause more confusion than a missing one, so when in doubt, leave it out unless a rule says otherwise.
The apostrophe replaces the missing letters: "could not" becomes "couldn't" (the apostrophe sits where the "o" was).
Singular possessor or irregular plural: add apostrophe + s. "The dog's bone." "The children's toys." "The geese's flight."
Possessor already ending in "s" or regular plural: add just an apostrophe after the existing "s." "The dogs' park." "Rufus' bone."
Possessive pronouns (his, hers, its, theirs, ours, mine) never use an apostrophe. "The rabbit is hers" is correct. "Her's" is always wrong.
A common confusion: "its" (possessive, no apostrophe) vs. "it's" (contraction of "it is"). If you can substitute "it is," use "it's." Otherwise, use "its."
Convey strong emotion. Use sparingly, especially in academic writing. The emotional impact of writing should come from your words, not your punctuation. Overusing exclamation points makes them meaningless and distracts readers.
Two uses:
Connect two closely related independent clauses: "I wanted to go to the party; you know I'm always looking for a good time." The semicolon signals a stronger relationship than a period would.
Separate complex items in a list where items contain commas: "There are two ways to write: with a pen or pencil, which is cheaper but slower; or with a computer and printer, which is more expensive but faster."
For simple lists, use commas, not semicolons.
Common uses:
Before a list, preceded by an independent clause: "I gave you three jobs today: washing the car, cleaning your room, and folding your clothes."
To separate a title and subtitle: "Ancient Greece: From Prehistoric to Hellenistic Times"
To link two closely related ideas: "He knew there was only one option left to him: to fight."
Between two independent clauses when the second explains the first: "The senators remained entrenched: neither was willing to compromise."
A colon can signal a stronger connection between ideas than a semicolon.
Indicate a verbatim account from a source or identify speech in narrative writing.
Can signal irony or draw attention to a term being defined: 'Though people still use it, "irregardless" is not a word.'
Be careful using quotation marks for irony in academic writing; readers may mistake them for real quotations.
First word of a sentence
The word "I"
Proper nouns (names of specific people, places, things): "David visited Cincinnati"
Titles before names: "Principal Armstrong" (but not "my dad" unless replacing the name)
Directional names: "the South" (but not general directions: "driving north")
Countries, languages, holidays, days of the week, months (but not seasons)
Major words in titles (first and last word always capitalised; skip short prepositions and articles unless they begin the title)
All caps for emphasis is acceptable on social media but not in academic writing.
Titles of longer works: books, movies, musical albums, journals, newspapers, websites
Shorter works (poems, songs) go in quotation marks instead
Foreign words not yet adopted into English: "espresso con panna" ("espresso" alone is not italicised because it has been adopted)
Emphasis, used sparingly
Spell out numbers less than 10; use numerals for 10 and above
Spell out numbers that begin a sentence, or rewrite the sentence
Be consistent throughout a text
Generally avoid abbreviations in academic writing
Acceptable when the abbreviation has its own dictionary definition or is commonly known ("IRS")
Acceptable when the full phrase has been introduced first: "The Irish Republican Army, or IRA, was most active during the late 1960s."
Latin and reference abbreviations (i.e., e.g., et al.) can be used, but avoid stacking multiple abbreviations in a single sentence
Follow the specific style guide your course requires
Students often scatter commas wherever they pause when speaking. Commas follow rules, not feelings. Unless a rule puts one there, leave it out.
Students frequently add apostrophes to plural words that are not possessive. "The students passed" (plural, no apostrophe) vs. "The student's grade" (possessive, apostrophe). If the word does not own anything, it does not need an apostrophe.
Students confuse "its" and "it's" constantly. "It's" is always a contraction of "it is." "Its" is the possessive form. No exceptions.
Students overuse semicolons, treating them as fancy commas. A semicolon joins two independent clauses (each could be its own sentence). It does not replace a comma in a list unless the items contain internal commas.
⚠️ Know the comma rules for lists, compound sentences, complex sentences, and introductory phrases.
⚠️ Be ready to distinguish possessive apostrophes from contractions, and to recognise that possessive pronouns never take an apostrophe.
⚠️ Expect questions asking you to choose between a semicolon, a comma + conjunction, or a period to fix a run-on.
⚠️ Know when colons are used (after an independent clause, before a list or extended idea).
⚠️ Be able to apply capitalisation rules to titles, proper nouns, directions, and days/months.
True or false: a comma alone can separate two independent clauses.
"The dog's bone" shows ________ (possession/contraction).
True or false: "it's" is the possessive form of "it."
A semicolon joins two ________ clauses.
True or false: the names of seasons should be capitalised.
Answers: 1. False (that creates a comma splice; you need a conjunction or a semicolon). 2. Possession. 3. False ("it's" = "it is"; the possessive form is "its"). 4. Independent. 5. False.
Q: Fix the punctuation: "Ski resorts, can be ideal locations for a family vacation."
A: Remove the comma. "Ski resorts" is the subject and should not be separated from the verb: "Ski resorts can be ideal locations for a family vacation."
Q: Add the missing comma: "If skiing is too intimidating snowshoeing can be fun."
A: The dependent clause comes first, so add a comma after it: "If skiing is too intimidating, snowshoeing can be fun."
Q: Is this correct: "A tutors skills may help a students performance"? Fix it.
A: Both need possessive apostrophes: "A tutor's skills may help a student's performance."
Q: When do you use a semicolon instead of a period between two clauses?
A: When you want to signal a stronger relationship between the two ideas than a period would. Both clauses must be independent (able to stand alone as sentences).
Q: Capitalise correctly: "i'm from the south, but i'm driving north."
A: "I'm from the South, but I'm driving north." "I" is always capitalised. "South" as a regional name is capitalised. "North" as a general direction is not.
Comma rules link directly to the clause and conjunction material in Constructing Sentences. Apostrophe rules connect to pronoun choice (possessive pronouns never take an apostrophe). Quotation mark conventions become essential in the Narrative Writing notes when you study dialogue. The capitalisation and style conventions here carry into any research or argumentative writing you do later in the course.
Comma, comma splice, apostrophe, contraction, possessive, possessive pronoun, semicolon, colon, exclamation point, quotation marks, capitalisation, proper nouns, italics, numbers in writing, abbreviations, punctuation rules, compound sentence punctuation, complex sentence punctuation, introductory phrase, Oxford comma, Sophia Pathways ENGL 1