I have an idea that might interest some of you.
I would propose that the Gospel of Matthew was written by Matthew in a two-part process. In his first “edition” he recorded a collection of sayings and this document was the first recorded gospel. I would suggest that the language used was Aramaic. Let me refer to this document as “proto-Matthew”. A number of years later Matthew saw the value of contextualizing this collection of sayings in the narrative recorded by Mark (the pristine version with the original ending), and he did so, enhancing it with additional material. The result was the Gospel of Matthew. I would suggest that the language used at this stage was Greek. Being the composition of Matthew, this document superseded proto-Matthew and proto-Matthew ceased to be circulated.
Proto-Matthew is Quelle. Luke would have had access to it.
Note that this proposal synthesizes the Two Source Hypothesis and the Augustinian Hypothesis, retaining the most compelling elements of both.
As an aside, but pertinent with respect to the projected format of Quelle, I would suggest that the Gospel of Thomas in its pristine form was written soon after proto-Matthew, and in the same format.
I would welcome your comments on this idea.
[Non-text portions of this message have been removed]