May not be the best person for this but my (very basic) understanding
The Oxford comma is used to seperate listed items eg eggs, toast, and orange juice. Notice the comma separates toast and orange juice? This implies they are two seperate items, where as without the comma, it implies that they are one item. Hence the orange juice on toast in the second image.
When listing things, the Oxford comma is when you put a comma before the "and" just before the last item on the list.
.
Oxford Comma: I need to collect the tears of my enemies, my mother's bones, a swallowed tooth, and a fish.
.
Without Oxford Comma: I need to collect the tears of my enemies, my mother's bones, a swallowed tooth and a fish.
.
Notice how the last comma is gone in the second example. This is what many English teachers say is correct, and it's horrid.
Some of my teachers always corrected this, others did not.. I never not used the oxford comma, and finally they stopped correcting me. (To be honest, those correcting me were Swedish-born english teachers, and those who didnt were from the UK... so I just did what "the experts" said)
Actually, it is considered both correct and incorrect. About 50% of English professors view it as correct and about 50% of English professors view it as incorrect. I've been taught both, even in college.
You see, these 3 things are known for single purposes, it is common knowledge to know that we do not use orange juice as a bread spread. By using the 'and' without the comma the sentence is still correct because we know that when someone says the words "I had eggs, toast and orange juice" it is common knowledge that the person had a cup/bottle/carton of orange juice.
The Oxford comma is used to seperate listed items eg eggs, toast, and orange juice. Notice the comma separates toast and orange juice? This implies they are two seperate items, where as without the comma, it implies that they are one item. Hence the orange juice on toast in the second image.
.
Oxford Comma: I need to collect the tears of my enemies, my mother's bones, a swallowed tooth, and a fish.
.
Without Oxford Comma: I need to collect the tears of my enemies, my mother's bones, a swallowed tooth and a fish.
.
Notice how the last comma is gone in the second example. This is what many English teachers say is correct, and it's horrid.
>it's even pointless in the picture, proving my point