Why is the Quran in Arabic?
The Quran is in the Arabic language because Muhammed, the Messenger of Allah and the first Muslims were Arabs (Fussilat 41:44). Every messenger (Rasoul) was sent in the language of his own people (Ibrahim 14:4). That the languages are different, is a sign of Allah (al-Rum  22). The common belief that the language of Paradise is Arabic, is not based on a trustworthy source (Bekir Topaloglu, “Cennet (Djannah),” Islamic Encyclopedia of Diyanet, VII, 383).