If a phrase or a sentence is not punctuated correctly, the intended meaning of a message changes completely. A serious message can become a joke and vice versa. Look at the following examples:
1. An English teacher gave a sentence and asked her students to punctuate it correctly: Woman without her man is a savage.
A) Most boys wrote: Woman, without her man, is a savage.
B) Most girls wrote: Woman: without her, man is a savage.
2. Another teacher gave an unpunctuated letter to his class and asked the students to use appropriate punctuation marks in the letter.
A) Dear John, I want a man who knows what love is all about. You are generous, kind, thoughtful. People who are not like you admit to being useless and inferior. You have ruined me for other men. I yearn for you. I have no feelings whatsoever when we’re apart. I can be forever happy — will you let me be yours? Betty.
B) Dear John, I want a man who knows what love is. All about you are generous, kind, thoughtful people, who are not like you. Admit to being useless and inferior. You have ruined me. For other men I yearn. For you I have no feelings whatsoever. When we’re apart I can be forever happy. Will you let me be? Yours, Betty.
(Source: www.enterarena.blogspot.in/2011/12/english-punctuation-jokes.html)
In the above examples, A and B have exactly the same words but, with punctuation marks at different places. The meaning between A and B, in each case, is very different.
Here is another example:
A) My sister, who is in Australia, is an aeronautical engineer.
B) My sister who is in Australia is an aeronautical engineer.
Sentence A implies that I have only one sister and sentence B implies that I have more than one sister. In sentence A, the clause ‘who is in Australia’ is a non-essential element and an additional information whereas in sentence B ‘who is in Australia’ is an essential element. The rule is we should not use commas to set off essential elements of a sentence as in the following examples:
• The movie that we watched yesterday is based on one of Chetan Bhagat’s novels.
• Two students who cheated on yesterday’s maths examination were debarred.
• The gentleman talking to the lady is my boss.
We should use commas to set off non-essential elements as in the following examples:
• Ramesh, who is a very rich student, gets five hundred rupees as pocket money from his father.
• The movie 3 idiots, which we watched in Bangalore last month, is based on a novel by Chetan Bhagat.
• My cousin, wearing a blue suit, is leading the group.
• Dhoni, the captain of the Indian cricket team, is going to be our chief guest.
Can you find the difference in meaning between sentences A and B below ?
A: Let’s eat, grandma.
B: Let’s eat grandma.
— rayanal@yahoo.co.uk