In the case that I’m not an expert in a field of Persian and English literature, I just guide you to some links and I little tip. Dear friends Iranians talk and write in Persian language we don’t talk and write in Arabic although our alphabet is really close to Arabic alphabet and actually it’s Arabic alphabet but we have our special charters as well, we have 4 letters that Arabs don’t have:[p], [tʃ] (ch), [ʒ] (zh) and [g], you can see more details in Persian language article and Persian alphabet article in wikipedia.
But what it is do with Persian or Farsi? well as I told you before and I’m sure you know it before, our language’s name is Persian but because of some reasons during this 3 or 4 decades more and more people are going to call it Frasi instead of Persian and thats wrong, Persian’s local name was Parsi and after Arabs came to Persia (Iran) in the case that they don’t have [p] they call it Farsi and during the time even Iranians themselves call it Farsi as well, but still in western and other languages the original name of Persian or Parsi remains. During these recent 3 or 4 decades and because of massive Iranian immigrants in foreign countries when foreigners asked them “well dude whats your language?” because most of them didn’t know foreign languages very well they simply answered “Farsi” this is one of the reasons you can find more reasons in the links and articles that I will put at the end of the note.It’s like Japanese people who call they homeland “Nippon” or “Nihon” but the international name is “Japan”, just like the same case about Finish people and their “Suomen Tasavalta”, when you say Persian you are talking about a big language family that is spoken in at least 4 countries with some versions such as Dari and Tajik. Therefore Iran and Persian culture easily comes in the listeners mind (Persian Rug, Persian Gulf, Persian Empire &…) But when you say Farsi its absolutely nonsense: “OK dude, where this Farsi is exactly spoken?”
My post about the same issue in my Persian blog.
Please follow these links and read it from the point of experts:
Persian or Farsi? The debate continues… (in English)
“Farsi” Recently Appeared Language! (in English)
Persian Language in English wikipedia
Persian or farsi? (in English)
Iran and Pesian language in west (in Persian)
No more farsi (in English)
Persia or Iran, Persian or Farsi (in English)
The Iranian Language Family (in English)
[edited] check also:
Persian or Farsi? (in English)
Me a Farsi or Persian language speaker? (in English)
Farsi or Persian? (in English)
(updated Feb 08) :
Farsi, is this a New Language?
Farsi or Persian? (in English)
Persian or Farsi? (in English)