Persian is a member of the Indo-Iranian branch of the Indo-European family of languages. The other branches of this family include, among others, Roman and Germanic languages, which include French and English, etc. On the other hand, Arabic is a member of Semitic languages, which is a completely different family. So, the grammar of Persian is very different from that of Arabic. But the vocabulary is somewhat shared, because a lot of Arabic words have entered the Persian language after the Arab Conquest of Iran.