Because – in my world – grammar is scary, I do what I can to make it friendly. Who can be afraid of these guys?
Comma’s seem to be the inspiration for many stressful sentences. Do we use a comma after But or too or to or not? Yes, sometimes. Therein lies the problem. When in doubt, we go to the source – the Chicago Manual of Style.
So, what is the comma for? We see them in sentences and we pause. A comma is a pause. In written dialogue it tells us the speaker swallowed, or took a breath or paused to search for a word. It’s not a long enough break to require a new sentence. It’s a tiny pause.
The comma also separates words for clarity. And this is where we bring in the Oxford comma my two friends are talking about. Sorry, Blue, it has nothing to do with shoes, unless it’s a list of shoes.
→ In her closet, she has twelve pairs of shoes including high heels, flats, boots, flip flops, and slippers.
See that comma after flops? There is your Oxford comma.
When a conjunction joins the last two elements in a series of three or more, a comma should appear before the conjunction. CMOS 6.18
One thing about grammar that I do find fascinating is – there is a name for absolutely everything. Even a comma that comes after at least three comma’s.