Punctuation is used to create sense, clarity and stress in sentences. You use punctuation marks to structure and organise your writing.
You can quickly see why punctuation is important if you try and read this text which has no punctuation at all:
perhaps you dont always need to use commas periods colons etc to make sentences clear when i am in a hurry tired cold lazy or angry i sometimes leave out punctuation marks grammar is stupid i can write without it and dont need it my uncle Harry once said he was not very clever and i never understood a word he wrote to me i think ill learn some punctuation not too much enough to write to Uncle Harry he needs some help
Now let's see if punctuating it makes a difference!
Perhaps you don't always need to use commas, periods, colons etc. to make sentences clear. When I am in a hurry, tired, cold, lazy, or angry I sometimes leave out punctuation marks. "Grammar is stupid! I can write without it and don't need it," my uncle Harry once said. He was not very clever, and I never understood a word he wrote to me. I think I'll learn some punctuation - not too much, enough to write to Uncle Harry. He needs some help!
Use the sections below to learn how to make your English clearer and better organised.
The Period, Full Stop or Point
The period (known as a full stop in British English) is probably the simplest of the punctuation marks to use. You use it like a knife to cut the sentences to the required length. Generally, you can break up the sentences using the full stop at the end of a logical and complete thought that looks and sounds right to you.
Mark the end of a sentence which is not a question or an exclamation
Rome is the capital of Italy.
I was born in Australia and now live in Indonesia.
The Dalai Lama is the spiritual leader of the Tibetan people.
Indicate an abbreviation
Many abbreviations require a period. Dr, Mr, Mrs, and Ms do not take a period in British English, nor do most abbreviations taken from the first capital letters such as MA, Phd, or CIA. In American English, some of these do require periods or both usages are correct (with and without periods). If you require 100% accuracy in your punctuation, refer to a detailed style guide for the abbreviation usage rules in the variety of English you are using.
I will arrive between 6 a.m. and 7 a.m.
We are coming on Fri., Jan. 4.
Often you will see a sentence concluding with three dots. This indicates that only part of the sentence or text has been quoted or that it is being left up to the reader to complete the thought.
The Lord's Prayer begins, "Our Father which art in Heaven..."
He is always late, but you know how I feel about that...
Period after a single word
Sometimes a single word can form the sentence. In this case you place a fullstop after the word as you would in any other sentence. This is often the case when the subject is understood as in a greeting or a command.
Periods in numbers
Numbers use periods in English to separate the whole number from the decimal. A period used in a number is also called a "decimal point" and it is read "point" unless it refers to money.
$10.43 = ten dollars and 43 cents
14.17 = fourteen point one seven
There are some general rules which you can apply when using the comma. However, you will find that in English there are many other ways to use the comma to add to the meaning of a sentence or to emphasise an item, point, or meaning.
Although we are often taught that commas are used to help us add 'breathing spaces' to sentences they are, in fact, more accurately used to organise blocks of thought or logical groupings. Most people use commas to ensure that meaning is clear and, despite grammatical rules, will drop a comma if their meaning is retained without it.
Separate phrases, words, or clauses in lists
When making a list, commas are the most common way to separate one list item from the next. The final two items in the list are usually separated by "and" or "or", which should be preceeded by a comma. Amongst editors this final comma in a list is known as the "Oxford Comma".
A series of independent clauses (sentences)
I met Harry, we went for a swim together, and afterwards Harry went home.
I like your son, I might even love him, but he is not a very good soccer player.
A series of nouns
For dinner I had soup, fish, chicken, dessert, and coffee.
This afternoon I went to Oxford Circus, Picadilly, Hamstead, and Gatwick Airport.
A series of adjectives
A list of adjectives usually requires commas. However, if an adjective is modifying another adjective you do not separate them with a comma (sentence 3).
She was young, beautiful, kind, and intelligent.
The house we visited was dark, dreary, and run-down.
She was wearing a bright red shirt.
A series of verbs
Tony ran towards me, fell, yelled, and fainted.
The boy leapt, spun, twisted, and dove into the water.
A series of phrases
The car smashed into the wall, flipped onto its roof, slid along the road, and finally stopped against a tree.
The dog leapt into the air, snatched the frisbee in its mouth, landed, and ran off into the forest.
Use a comma to enclose non-defining relative clauses and other non-essential details and comments. The comma is placed on either side of the insertion.
China, one of the most powerful nations on Earth, has a huge population.
Jason's grandmother, who was born in 1930, lived through the Second World War.
Cats, unlike dogs, do not respect their masters.
My friend, Jim, likes to go scuba diving.
Hearing that her father was in hospital, Jane left work immediately.
Walking to the bus stop that morning, Sam knew it was going to be a special day.
She lives in Paris, doesn't she?
We haven't met, have we?
Yes, I will stay a little longer, thank you.
No, he isn't like other boys.
Wait, I didn't mean to scare you.
A final warning
Putting a comma in the wrong place can lead to a sentence with a completely different meaning, look at these two sentences:
I detest liars like you; I believe that honesty is the best policy. = I detest you because you are a liar.
I detest liars, like you; I believe that honesty is the best policy. = You and I both detest liars.
The Exclamation Mark
The exclamation mark is used to express exasperation, astonishment, or surprise, or to emphasise a comment or short, sharp phrase. In professional or everyday writing, exclamation marks are used sparingly if at all.
You can also use exclamation marks to mark a phrase as humourous, ironic or sarcastic.
What a lovely day! (when it obviously is not a lovely day)
That was clever! (when someone has done something stupid)
In very informal writing styles (SMS, chat, Twitter or Facebook, etc.), an exclamation mark is sometimes combined with a question mark to indicate both surprise and slight uncertainty. Double and triple exclamation marks are common in very informal writing styles, but are a sign of being uneducated in less casual correspondance.
Examples of casual writing
He's getting married!?