he did not speak a prophecy. He prophesied, which is not the same as prophecy in context to tongues and interpretation.
Incorrect.
"Prophesy" in all of its forms is the same. I.e. - The individual SPEAKS WORDS that are sourced to their mind by the Holy Spirit. They (hopefully) add nothing to it, and subtract nothing from it. Baalam is an example (Num 22) - he wasn't on God's side AT ALL, and wanted Balak's MONEY, but COULD ONLY say what God gave him to say prophetically. (Paranthetically, is Hebrew "tongues" for a donkey??)
Observation: I was in a church for many years and a certain brother in the church would spout off in tongues with regularity at the same point in the service almost every service. And his "utterance in tongues" was always the SAME - same words, same order of words, same length of utterance. SO - obviously I "wrote him off" as a flake somebody "religious" who was scratching his itch.
UNTIL - after I had been "baptized in the Holy Spirit" (to use Assembly of God terminology), and in an evening service (remember them??) He ripped off his "Tongue" - and I was FOR THE FIRST TIME burdened to Interpret, when he got through. I learned two things: that I shouldn't be so judgmental about somebody's gift even if it seemed stupid to me,
And The interpretation of a "tongue" isn't
necessarily a "Translation" of the tongue - since his tongues were always interpreted, and the interpretations were all over Robin Hood's barn - EVEN THOUGH his utterance in tongues was always the same.
I formed the PERSONAL OPINION, that often "Tongues" in a church meeting context, are primarily a "Trumpet sound", as it were, to get our attention for the interpretation to follow (arguably a prophetic word).
I've been in the "FUll Gospel" genre for about 59 years, and can still count on the fingers of both hands the number of times a tongue was spoken in service, and there was NO Interpretation given probably in about 30% of the instances by another member of the congregation.
And YES!!! I know of cases (unless all our AG pastors and Missionaries are bald faced LIARS) where a tongue was spoken AND understood by somebody present accompanied by an interpretation that matched what the tongue had said when understood. Also there are reports, of a message in the "Common tongue" being delivered, and HEARD in one or more other languages. and quite a few accounts of tongues being spoken in a more private setting, which were a message is to an individual hearing them in their own language, even with the proper regional accent.
God, after all isn't a "One trick pony".