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.