I’ve been proof reading a script and, not for the first time, I have been dismayed by the lack of commas. Commas change the meaning of a sentence, making the difference between separate clauses and concatenation.
Proof reading in a different field, Dawn Laker of Plot Bunnies pointed out the difference made by a comma in a list. She found
…whether you’re on holiday at a wedding…
In the absence of a comma, the writer appears to believe that a wedding is a vacation destination.
In my case, I’ve been falling over the failure to create an addressee clause. Addressee clauses are features of reported speech – so very common in plays. The most familiar illustration of this is the difference between
Let’s eat, Grandma!
Let’s eat Grandma!
The first is an enthusic invitation to dine with a relative, the second an invitation to dine on a relative.
The subject of that sentence is “us”. (Let us eat.) Omitting the comma adds an object to the sentence: the thing that we are going to eat. (Let’s eat pizza.) Adding the comma creates a separate clause, making it clear to whom the sentence is being addressed.
I have seen an objection to this example. The argument runs that since we are not cannibals, the meaning is clear with or without the comma. Even if you believe that argument (and I don’t think you should), it does not absolve you from the need for addressee clauses. Take a look at the following:
Are you sure you can manage Dad?
As written, Alice is asking Tom if he can manage their father. The subject of the sentence is “you”, the object (the thing being managed) is “Dad”.
With a comma, this becomes
Are you sure you can manage, Dad?
The comma makes it clear that we have an addressee clause: Alice is asking her father if he can cope on his own.
I discussed this phenomenon with Bob Heather a while back. Bob offered an illustration coming from the opposite perspective (the spurious addressee clause), the rather disturbing:-
What is this thing called, Love?