In Spanish, if I list the pets at home, I say:
En casa hay un perro, un gato, una araña y una serpiente. After the third, no comma is required.
But if a say that in English, it seems that there is a conflict between the British and American variations when I write:
At home there is a dog, a cat, a spider, and a snake.
The spelling checker from "Word" when set to American English insists in requesting a comma before "and". When set to British English, it does not complain.
I recall something writen by jpanhalt where he used that comma before "and".
Rule or just common use? Comments appreciated.