Medieval Muslims were reluctant to travel to infidel lands. According to Islamic jurists Muslims should not stay for too long in the lands of non-Muslims if they cannot live a proper Muslim life there. Muslims had little knowledge of or interest in any Western languages. Only Italian had some currency for commercial purposes, but mainly involving Jews and Eastern Christians, especially Greeks and Armenians. Few Muslims knew any non-Muslim languages well, the knowledge of which was considered unnecessary or even suspect.
Consequently, the translators of Greek and other non-Muslim scientific works to Arabic were never Muslims. They were Christians of the three dominant Eastern denominations plus a few Jews and Sabians. The language of culture for these Christians was Syriac (Syro-Aramaic or Eastern Aramaic) and their liturgical language was Greek. The translators already knew the languages they were to translate. We do have examples of translators who traveled to Greece to perfect their skills, but they were Christians for whom Greek was already at least a liturgical language. [emphasis mine]
Originally from: The Brussels Journal.