Commas in a Series
In English you can use series commas when you list items. Separating items in a list helps clarify things. Imagine that you text a shopping list to your roommate Charlie, who’s at the store shopping for your birthday party. Everything’s on one line.
flashlight batteries butter cookies ice cream cake
How many things does Charlie have to buy?
How does Charlie know? He doesn’t, unless you use commas. Here’s what Charlie actually needs to buy — all four items:
flashlight batteries, butter cookies, ice cream, cake
To put it in a sentence:
Charlie has to buy flashlight batteries, butter cookies, ice cream, and cake.
The commas between these items are signals. When you read the list aloud, the commas emerge as breaths:
Charlie has to buy flashlight batteries [breath] butter cookies [breath] ice cream [breath] and cake.