A perfectly concise explanation of direct address commas from Erin Brenner of Right Touch Editing. Be sure to check out her wonderful blog, thewritingresource.net.
“The comma rule depicted here is simple: use a comma with the name of a person you are directly addressing. If the name comes first, it is followed by a comma:
Children, please stop jumping on the beds.
If the name comes at the end of the sentence, the comma precedes the name:
Stop jumping on the beds, boys.
And if the name (or names) comes in the middle of the sentence, surround it with commas:
What I said, Sean and Duncan, was to stop jumping on the beds!
As you can see from my example sentences (other than my children’s habit of jumping on the beds), you don’t have to use a proper name to address someone. A title works, even an informal one like boys.
In the cartoon, the comma changes the sentence from a bothersome one about cannibalism to a friendlier one about a grandchild encouraging Grandpa to have something to eat (as long as it’s not Grandma). Got it? Good. Let’s try a quick quiz.
- Arthur you really should consider running for office again.
- When Arthur ran last time, he lost by just a few votes.
- Don’t you want to go the distance Arthur?
- Right now Arthur is the best time to campaign.
- Just because the election is two years away is no reason for Arthur not to start knocking on doors.”
see the full link here: https://www.vocabulary.com/articles/wc/punctuation-point-the-direct-address-comma/