I was joking about it being a different Matthew and this is the first time I’ve ever heard that his gospel was originally in Hebrew. Who came up with that idea?
Some believe that it was originally in Hebrew because it was written to Jews by a Jew who was a tax collector for the Roman government. Mathew presents Christ as the son of David and son of Abraham and characterizes Jerusalem as the holy city.
The original Matthew might have been the Matthias chosen to sub for Judas who busted his gut, but whether this is right or not the idea goes back to Schleiermacher and the other biblical NT scholars of the 1800s. The original circle of 120 who met in the Upper Room were mostly Jews so most were literate and were keeping notes so Luke could compile his accurate history in two books. They all would have had access to this hypothetical original Matthew in Hebrew.