What are the differences between the Persian and Arabic script and alphabets?

persian is a really old language and the old writing (old Pahlavi alphabet of Persia or the Avestan alphabet) doesn't exist anymore. Avestan is an extinct Indo-Iranian language related to Old Persian and Sanskrit and was created in the 3rd century CE. The Avestan alphabet was replaced by the Arabic alphabet after Persia converted to Islam during the 7th century CE. The alphabet is written from right to left, in the same way as Syriac, Arabic and Hebrew. Persians use a modified version of the arabic alphabet. And also use a lot of arabic words (specially iranian persians) even if they already have those words in persian. Although the two languages share the same alphabet some letters are pronounced slighlty differently in Persian than in Arabic. The Four letters which are in the Persian alphabets but not in the Arabic alphabet are: Peh = پ = P in People Cheh = چ= Ch in Chart Gaf = گ= as G in Game Jeh = ژ= Does not have an equivalent in English; nearest letter is J like the way "asia" is pronounced the letter yah =ي has 2 dots in Arabic but doesn't have any dots in persian. The letter yah without dots in arabic is called alef maksura and is pronounced like the letter alif = ا = "A" in english. Iranian persians pronounce the letter quaf = ق --> gh like "R" in french.