Languages of the Ottoman Empire
The Ottomans had three influential languages: Turkish, spoken by the majority of the people in Anatolia and by the majority of Muslims of the Balkans except in Albania, Bosnia, and various Aegean Sea islands; Persian, initially used by the educated in northern portions of the Ottoman Empire before being displaced by Ottoman Turkish; and Arabic, used in southern portions of the Ottoman Empire; Arabic was spoken mainly in Arabia, North Africa, Mesopotamia and the Levant. Throughout the vast Ottoman bureaucracy Ottoman Turkish language was the official language, a version of Turkish, albeit with a vast mixture of both Arabic and Persian grammar and vocabulary.
Firman of Karamanoğlu Mehmet Bey
Agop Dilaçar, who is known for his works on the Sun Language Theory, claimed that Mehmed Bey might have declared Turkish the official language of the state. According to Dilaçar, in his firman dated 13 May (15 May ?) 1277, he ordered that "from that day forward, in the council, in the dervish lodge, in the court, in the assembly, in the square, no language but Turkish should be spoken".
Before him, the Seljuq elite in Anatolia used Persian in literature and Arabic in government and science. The Turkmen, however, could not understand these languages.