What is punctuation?
Punctuation is used with written English. It has two main purposes. The first is to help readers to understand how the words would sound if they were spoken, and the other purpose is to help readers understand the grammar of a sentence. Clear and correct punctuation makes written English easier to understand, and sometimes the use of punctuation can completely change the meaning of a sentence.
Consider this famous example:

'Woman without her man is nothing.'
This has the meaning that if a woman does not have her man, then she is nothing. But now let's add some punctuation.
'Woman; without her, man is nothing.'
The meaning is now the opposite. The sentence says that men are nothing without women. Punctuation is important for meaning.

Punctuation is different for every language - for example Spanish uses an upside-down question mark at the start of a question, but English does not. So even if you know punctuation in your own language, it is still necessary to learn how this is done in English.

What is the best way to learn punctuation?
Punctuation is best learned by looking at written English and trying to understand how the use of punctuation changes the way a sentence is read. Try reading sentences aloud, and notice the effect that punctuation has on the rhythm of your speech. Note that some types of written English, such as cartoons use non-standard punctuation, so try to read English in a novel or a newspaper. When you have written something, read it through aloud. If you have difficulty or find yourself running out of breath,then you have punctuated badly. Remember that spoken English allows the speaker to use stress, timing and intonation. When reading written English, look to see how punctuation tries to reproduce this.

What punctuation is covered in this unit?
In this unit we will look at the comma, the semi-colon; and the full stop. You may think you know about these already, but there are some details that will still surprise you.

The comma

As we have seen, one of the jobs of pronunciation is so that written text can be understood as speech. All speech has a natural rhythm. We say parts of a word (syllables) at a certain speed, and pause between them for a certain time. If the speed we say each syllable of a word is one beat, then a comma is a pause in the sentence for the same amount of time - one beat.
For example:
This sentence
'Susan can tell Bill if she can't tell Janet.'
can be made into syllables with the same beat like this
'Sus-an-can-tell-Bill-if-she-can't-tell-Jan-et.'
This sentence means that if Susan doesn't want to speak to Janet, she can speak to Bill.
However, now say this
'Susan-can-tell-Bill (pause)if-she-can't (pause) tell-Janet.'
The places where there is a pause are where the comma in speech is shown by a silence lasting as long as it takes to say one of the syllables.
If you study this sentence you will see that because of the commas/pauses, the meaning is now changed. The first sentence is about what happens if Susan can't speak to Janet. The second sentence tells someone else to inform Janet if Susan can't speak to Bill.

When do we use commas?
As you have seen, when we would pause for one beat in normal speech, we should insert a comma into written text. This is because, as we have seen, sometimes whether or not a sentence has a comma can change the meaning. It is also necessary sometimes to show how the parts of a sentence fit together.
For example:
'The beer, barrels, and the wine glasses were gone.'
is not the same as
'The beer barrels and the wine glasses were gone.'
In the first sentence beer, barrels and wine glasses are three seperate things. There might have been wine in the barrels or they might have been empty. In the second sentence we know that the barrels had beer in them, because without a comma we treat 'beer barrels' as a single idea.

Commas are used to join clauses that would otherwise be two sentences.
For example:
'Don't be late. Because otherwise I'll go without you.'
has the same meaning as
'Don't be late, because otherwise I'll go without you.'
Often commas are used with link words which join the clauses, such as 'because' 'and' 'or' and 'so'

Commas also show you which parts of a sentence belong together.
For example:
'Go down Oak Avenue, turn left at the post office, and then go down River Road.'
This sentence uses commas to group the instructions into sets of actions. A famous example of this being done wrongly is of the Australian animal which 'eats, shoots, and leaves'. The commas as used here in the sentnece group the actions into eating, firing a weapon, and departing.
However, properly written, the sentence tells us about the animal's diet - it eats roots, shoots and leaves. ('Shoots' are new, green twigs)

'Gapping' commas
Sometimes a comma is used to show that the reader is expected to understand that an extra idea needs to be inserted to complete the sentence.
For example:
we could say:
'In England people speak English and in France people speak French.'
However, we do not need to repeat 'people speak' in the sentence. We can show the idea by a comma. So we can use this sentence instead.
'In England people speak English and in France, French.'

The Semi-colon

Where a comma takes one 'beat' of normal speech, the semi-colon, like the full stop, takes two. This is because a semi-colon is used to put two separate clauses into one sentence, often without using a link word.
For example:
'Tell me what you want. I'll help if I can.'
can be written as
Tell me what you want; I'll help if I can.

Link words with semi-colons
Some link words can be used with semi-colons because they show that even if the clauses are grammatically independent, they carry on the same idea.
For example:
'Semi-colons do not need link words; however this does not mean we never use them .'
'Semi-colons are useful; therefore it's a good idea to use them.'
'He used a semi-colon; consequently his text was more understandable.'
'Use semi-colons; otherwise there's no point in learning about them.'

Placement of semi-colons
Like commas, a semi-colon in can change the meaning of a sentence depending on where it is placed. Consider the example below.
For example:
There was one surprise only Janet was coming.
This can mean
'There was one surprise only; Janet was coming.'
That is, that there was just a single surprise, that Janet was going to come as well.
'There was one surprise; only Janet was coming.'
Here however, the surprise is that no-one but Janet is coming.

Semi-colons with lists
Semi-colons are often used to give lists
This is especially true when the list contains extra descriptive detail which can be confusing. So if we read
'Fred went out with Janet, his girlfriend and his secretary.'
How many people did Fred go out with?
If Janet is Fred's girlfriend and also his secretary, Fred went out with just one other person. However commas alone do not tell us if there were two, three or four people in the group. A semi-colon tells us that there were three people.
'Fred went out with Janet, his girlfriend; and his secretary.'

The full stop

In American English this is called the 'period'. We see it most often at the end of the sentence. One of the most common errors with the full stop is that it is sometimes wrongly replaced with a comma. Remember, if you are intrducing two separate facts it is best to use separate sentences, or at least a link word.
For example:
Greece has a very long coastline. Switzerland does not have a coastline at all.
is correct. So is
Greece has a very long coastline whereas Switzerland does not have a coastline at all.
is also correct. However, these two separate facts cannot be linked by just a comma.

Full stops are used to indicate abbreviations where the word has been cut short. Though there are many different methods to use when deciding whether or not to use a full stop, it is less important which rule you use, and more important that you use the same rule all the time. A good rule is that you can sometimes use full stops with an abbreviation but not with a contraction.

A contraction is when we actually say the word as it is written (For example we say 'ten o'clock' as it is written, instead of the long form which is 'ten of the clock'. 'Can't' is a contraction of 'cannot', and the two words are said differently.)
An abbreviation is when a word is written in a short form, but when read aloud, the whole word is said. (For example, we may write '$' or 'Dr' but we say these aloud as 'dollar' and 'Doctor'.)
In Britain, abbreviations do not have a full stop if they have the first and last letters. So 'Dr' and 'Mr' have no full stop but 'Av.' (for avenue) does and so so all initials - e.g. J.K. Rowling. Note that measurements are generally abbreviated without a full stop. So we have 'lb' and 'oz' for 'ounce' and 'kilogram'.

With acronyms (words made from the first letters of a longer phrase), the general rule is that if the acronym is an abbreviation we use full stops. For example with the World Health Organization, the abbreviation is W.H.O. because even if just the letters are used, they are spelled out individually. But we say 'Nato' because this is a contraction for the North Atlantic Treaty Organization and it is said as a word. Therefore full stops are not used between the letters.
Some abbreviations like Nato have become contractions because of frequent usage, So the USA ('Uesaye') and the BBC ('Beebesee') are not now written with full stops between the letters.

Also, remember that if you finish a sentence with an abbreviation that ends with a full stop, this full stop is also the full stop for the end of the sentence. So you would say that 'Mr Juarez works for the U.N.' with only one full stop at the end, even though this full stop finishes both the 'N' and the sentence.

Finally, note that with titles of (for example) chapters you do not use a full stop, which is why the titles of the sections in this text do not have full stops, although they sometimes have question marks.

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Okay, so we have learned commas, which have a few surprising uses; semi-colons, which are useful for lists like this; and full stops, where there are a few extra rules to learn; e.g. that we write 'e.g.' with full stops because this is an abbreviation of 'exempia gratia'. Now let's try some exercises!