Language:
The main language of the Byzantine Empire was known as Byzantine Greek. This language served as the language of administration and of most of the writing during the period of the Byzantine Empire. However, Byzantine Greek was not always the core language of the Byzantines. The original official language of the Byzantines at the time of its founding was Latin, the language of Rome. But, while the officials and higher placed nobles spoke Latin, the common local people of the area spoke Greek. Eventually, over time, Greek began to replace Latin as the official language of the government.
This is an example of what the Byzantine written language looked like. If you compare it to the Greek language below, you can tell that the two look very similar.
This here is an example of the Greek language. You can see the similarities of how the Byzantine and Greek language and how they differ from one another.