I've been wondering; If Jesus spoke Aramaic or some other dialect, then everything had to be translated into Greek. Add to that the very real possibility that several of the people that heard Jesus speak must have gone off and repeated the stories orally. The sayings of Jesus could have been spread orally in several different languages. I would think that at least some of the stories must have been "creatively" repeated and very different than the original words spoken by Jesus. Now, of course we have the written Gospels based on what is presumed to be the "original" Greek manuscripts. Yet, are even they, merely a translation?
their are no original gospels, everything was written after his death by a different culture, from a different geographic location.
jesus sayings are possibly preserved with Thomas and Q
But the rest is roman hellenistic theology
No they are not a translation, much of the gospels are just copied and layered. The first Gmark is still a roman piece, written for romans, far removed from judaism.
Gjohn is interesting because it has some older jewish sources as well, but it was compiled and redacted for a little longer then the others. problem is, its not dealing with historical jesus, as much as the johannine communities disagreement with judaism
all we can gather from this, is he was a traveling teacher of judaism in Galilee, a country boy preaching to small crowds in small villages, after being baptised by JtB. He went to the big city and hated the corruption he witnessed in the jewish governement/temple/treasury, and got violent and was put on a cross.
not much else can be said with to much certainity, including your questions of language.