Philosophy in the Islamic World

In much of the islamic world, arabic became and remained the primary language. Even in places that held on to their local tongue, like persia, it became an important and even dominant language for writing literature including philosophy. This is why philosophers from persia and central asia, including no less a thinker than avicenna, wrote in arabic - which was not necessarily their native language. On the other hand, would be a mistake to equate philosophy in the islamo-philosopher world with Arabic Philosophy.