Hi Larissa,
Very interesting and useful article for both English and Spanish learners. Thank you. However, I frowned a bit over your advice to put commas before "and" in a list in English.
I am English and was educated here in England. I was taught never to put a comma before "and" and "or" in a list. I researched this and it seems to be a difference between American and English "English". (Yes, another one just to confuse everyone!)
So I would write: "For students learning English, trying learn all the differences between American and English "English" must be difficult, confusing, infuriating and frustrating."
Take a look at this site which confirms this:
http://www.thewritingsite.org/british-english-vs-american-english/
Best wishes,
Christine