The relationship between Persian and Arabic

One of the most widespread misconceptions about Persian has to do with its relationship towards Arabic. Most people mistakenly believe that they are a single language, or that they are two very similar or closely related languages. Arabic belongs to the Semitic language family and is, therefore, not related to Persian, which belongs to the Indo-European family. Therefore, from the point of view of phonological, morphological and syntactic structure, there are no similarities between the two languages (even though a couple of syntactic structures have entered Persian from Arabic). On the other hand, after the advent of Islam in Iran and the subsequent spread of the Arabic language, many Arab words entered Persian, even though nothing changed in the nature of the morphological and syntactic structure. Maybe the most important similarity between the two languages is their writing system, because the Persian alphabet is very similarity to the Arabic, although the writing system of these languages does have mutual differences.