Eusebius' Ecclesiastical History (Book 3, Chapter 24), says of St. Matthew's Gospel that the saint "committed it to writing in his native tongue."
Of course, St. Matthew's "native tongue" was probably Aramaic, although Eusebius apparently thought it was Hebrew:
"Matthew also having first proclaimed the gospel in Hebrew . . . " (ibid).
So, did St. Matthew write his gospel in Aramaic or Hebrew?
Your guess is as good as mine.
I messed up my vote, BTW. I should have hit "Mostly Greek," but hit "Other" instead.