The comma is the shortest pause between words.
The comma has the following uses in a simple sentence.
To mark off nouns, pronouns or phrases in apposition
- James, my neighbor, is a doctor.
- Wordsworth, the famous English poet, was a lover of nature.
To mark off each one of a series of words belonging to the same part of speech
- He spoke easily, clearly and eloquently.
- The children laughed, danced, jumped and cried for joy.
A comma is generally not placed before a word preceded by and.
- The farmer owned sheep, cattle and poultry.
To mark off a nominative of address
- Doctor, the patient is ill.
- Gentleman, I bring good news.
After a nominative absolute
- God willing, we shall meet again.
To mark off a direct quotation from the rest of the sentence
- ‘I am not tired,’ said James, ‘but I am very hungry.’
To separate each pair of words connected by ‘and’
- Young and old, high and low, rich and poor, all praised the little boy’s clever tricks.
Before and after words, phrases and clauses let into the body of a sentence.
- His conduct, to say the least, was disgusting.
- He did not, however, agree.
The following words and expressions are also separated from the rest of the sentence by means of a comma: at least, indeed, well, all the same, however, of course, on the whole, in short, in particular etc.