Comma Use In a Sentence: the Interrupter -- Grammar Rules
What is an Interrupter?
An interrupter, well, interrupts the flow of a sentence, and can be in the form of a single word, a phrase, or a clause. Interrupters are used for emphasis, to indicate a switch in tone, to qualify a subject, or as a side note. Interrupters are usually punctuated with commas or em dashes on both sides of the word, phrase, or clause. Here are a few examples of interrupters punctuated with commas:
- For emphasis: My sister, to be honest, did not do her research.
- To indicate a switch in tone: The puppy wanted to play with string. The kitten, however, had a different plan in mind.
- To qualify a subject: Some pop stars, Katy Perry for example, will end up on reality televisions shows.
- As a side note: The iPhone 5, surprisingly, was not released before my birthday.
Interrupters can also be indicated with em dashes for more emphasis. Here are a few examples of interrupters punctuated with em dashes:
- For emphasis: I really wanted to try the steak--believe me--but I can't eat red meat on my new diet.
- To qualify a subject: The three piranhas--named Shimmer, Glimmer, and Sparkle--freaked out during the move.
- As a side note: I ordered a drink--the fruity kind--and some idiot knocked it over as soon as they served it.
Using an interrupter as a side note gives you, as the writer, a lot of freedom. It also means that the definition of an interrupter is very broad. The best way to decide whether or not to use a word, phrase, or clause as an interrupter is to ask whether it merits emphasis or is important enough to be singled out. If it is, it may be a good style choice to separate it with commas or em dashes.
Examples of Common Interrupters
Used with Commas
Used with Em Dashes
but I disagree
on the other hand
to say the least
to be honest
and I suppose that's right/correct
but I thought/wanted/voted for...