A translator's perspective
When an idea is originally put into words in language A, and is then translated into language B, unless the translation is done by a very skilled translator, the idea will flow better in language A: it will match the rhythm, idiom, and syntax of language A better than that of language B.
This is something I have observed in my own work with English & Spanish--I can often tell which is the original language and which is the translation.
Hebrew in the Gospels
Claude Tresmontant argued in The Hebrew Christ that there is immense evidence of original Hebrew beneath the Greek text of the Gospels. For example:
the LXX translations made a great effort to respect the Hebrew text as
much as possible, and to make their translation as strictly literal as
possible. There was no concern for the natural genius of the Greek
language. Both the order of words in Hebrew and the structure of
Hebrew phrases, are very special. First the verb, then the subject,
and after that come complements or prepositional phrases The Hebrew Christ p.12)
When we find in the Gospels phrases that have the composition, form,
structure, or constitution of a typical Hebrew expression, we may be
sure that such phrases are translations into Greek from the Hebrew.
Such translations tried to respect the structure and word order of the
Hebrew, just as the Septuagint translators tried to respect them.
In the aforementioned work, Tresmontant cites dozens of examples of these phenomena in the Gospels, and like Robert Lindsey (cited in the post linked by the OP), found that the Gospel of Luke was the most consistently Hebrew in syntax and expression of the four Gospels.
The scholars who made these discoveries did so by translating the Greek text into Hebrew--the way the material flows in Hebrew is no more evident in Greek than it is in English--the presence of Hebrew syntax and expression is apparent when the material is rendered in Hebrew.
Plays on Words
George Howard wrote extensively about the plays on words in the Gospel of Matthew--in Hebrew--that do not work in Greek (or English). Though there are scores of such examples in the Gospels, perhaps the most famous one is:
And she shall bring forth a son, and thou shalt call his name Jesus:
for he shall save his people from their sins (Matthew 1:21).
This is a play on words in Hebrew, because "Jesus" (Yeshua) in Hebrew refers to a savior or one who saves. The play on words is lost in Greek and in English. Plays on words in the original language are often difficult/impossible to pick up on in a translation until the text is translated back to the original language. Frequent play on words in a given language is a good sign that that language is the original.
Relevance to the Synoptic Problem
The overwhelming majority of scholarship seeking to solve the Synoptic Problem has focused entirely on the Greek language (an understandable place to start, since the Synoptic Gospels have come down to us in Greek). One of the results, however, is that each of the major theories on the Synoptic Problem must ignore some of the patterns in the wording in the Gospels, which, despite centuries of effort, remain inexplicable in Greek alone (e.g. see my videos on this subject here and here).
If Lindsey, Tresmontant, and others are correct that the Greek of one or more Gospels is a careful translation of material originally composed in Hebrew, it opens up a full new dimension to the Synoptic problem. Lindsey's theory on the Synoptic Problem worked only on the basis that the Gospel material was originally composed in Hebrew. So did Tresmontant's. So did Carmignac's. (so does mine, if anyone's counting :-)
In my own work on the Synoptic Problem I propose a modification (involving Hebrew) to the popular Two-Gospel Hypothesis which allows it to account for patterns in wording that remain inexplicable in Greek alone.
I am of the opinion that the Synoptic Problem cannot be solved without the Hebrew language. Modern scholars opened this door by recognizing (through translation) the underlying Hebrew thought, syntax, and expression present in the Greek text of the Gospels.
Appendix--Discussion of Syntax
A translator can produce a finished product anywhere along a spectrum from literal translation to literary translation. A fully literal translation often comes across as gibberish. A fully literary translation may mask the idea's origin in another language, and it may also lose some of the nuance of the original.
Consider the following examples of literal vs. literary translations:
- The Alexander the world conquered (this is an English sentence with Greek syntax--it's a fairly literal translation of ο Αλέξανδρος τον κόσμο κατέκτησε)
- Alexander conquered the world (same concept in a more literary translation)
- Himself he injured Alexander in the battle of Gaugamela (this in an English sentence with Spanish syntax--it's a fairly literal translation of se lastimó Alejandro en la batalla de Gaugamela)
- Alexander was injured in the battle of Gaugamela (same concept in a more literary translation)
The examples above are deliberately written to be very obvious; many day-to-day examples are more subtle. If one does not know the language in which an idea originated, or it is unclear, translating it into several languages can elucidate the presence of syntax, idiom, plays on words, or other patterns of an original language that are not immediately obvious when reading the translation.