Languages of the Ottoman Empire
The language of the court and government of the Ottoman Empire was Ottoman Turkish, but many other languages were in contemporary use in parts of the empire. Although the minorities of the Ottoman Empire were free to use their language amongst themselves, if they needed to communicate with the government they had to use Ottoman Turkish.
Dragoman of the Porte
In the Ottoman Empire, the existence of official interpreters or dragomans (from the Italian rendering "drog[o]man" of Arabic "tardjumān", Ottoman "terdjümân") is attested from the early 16th century. They were part of the staff of the "reis ül-küttab", who was responsible for foreign affairs within the Imperial Council. As few Ottoman Turks ever learned European languages, from early times the majority of these men were of Christian origin—in the main Austrians, Hungarians, Poles, and Greeks. 
In 1661, the Grand Vizier Ahmed Köprülü appointed the Greek Panagiotis Nikousios as Chief Dragoman to the Imperial Council. He was in turn succeeded in 1673 by another Greek, Alexander Mavrocordatos. These men began a tradition where almost all subsequent Grand Dragomans of the Porte were of Greek origin or Hellenized as members of a small circle of Phanariote families, such as the Mavrocordatos, Ghica, or Callimachi clans. Many of the Phanariotes had previously served in the staffs of the European embassies in Constantinople. Nikousios, for instance, had previously (and for a time concurrently) served as translator for the Austrian embassy.