The letter from Shlichim and Elders (Acts 15:23)

[bensocha]

I recently thought deeper about this piece of Scriptures and I asked myself a question: in what language the Shlichim and Elders wrote a letter to the brothers from Gentiles? They wrote to those who lived in Syria and Cilicia. People of Syria spoke Aramaic and people of Cilicia spoke Greek. Which language did they use to write the letter to them? We know for sure that they didn't produce two separate copies of the letter - one in Greek and one in Aramaic. The Scripture clearly says about "a one letter" in singular. What we also know is a fact that Paul, Bar-Naba and others were sent with the letter straight to Antiochia and they remained there for longer (verses: 22, 35). Does it mean that the original letter of Apostles and Elders was written in Aramaic? Is it not a logic conclusion? And maybe then someone from assembly of Antiochia travelled to Cilicia and translated this very letter into Greek for the benefit of believers in Cilicia? What do you think?

Thyank you and Shalom! :-)
Bartek