Not quite contrary to your sources I would try to relate this to the root of teach, Ger. zeigen, Lat. digit or dict-. The set ührase is "Zeichen deuten" and deuten is otherwise synonymous with zeigen. The semantic derivation--preceding a probably folk etymologic reinterpretation towards "deutsch"--would be *deyḱ-, show > teach > teach language > interpreter [e.g. of records] > explain to the tribe > ...
Compare lector, "someone [able to, in the profession] to read"; doctor "?"; ein Deut, chiefly used in "keinen Deut besser" (not one bit better), imaginably from "kein' Deut verstehen" ("to understand not one Deut"). Looking at talk, PIE *del- I come to think, the sequence of derivation may well be different, as a comparison Latin debeo, habeo and lego, elect and delinquo may suggest, as the latter relates to PIE *leykʷ- (perfective "to leave") deriving words relating to "remains" and "inheritance" in various languages, and interpretation of cultural heritage through oral tradition and associated cryptic signs is what I'm riffing on.
Speaking of dict-, compare pregnant "pre+gnoss-", i.e. showing first signs, foreboding, foretelling, vs idiomatic Ger. dicker Bauch "big belly", akin to thick, but with only Germanic and Celtic derivations at the PIE level. I'm saying dick stems from a sense "in-dic-ation"; ironically, big is rather uncertain and likely pertains to the root *bhew-, that's often glossed "to swell", whence also Ger. Bauch, "belly". The wonders of life, ey? Venus figurines of big belly girls are among the oldest pieces of art we know, around 30.000 years old.
I also see "dick" here, comparing "digitus".
I'm not sure how *tewteH-, "strong, powerfull, mighty" figures into this. Maybe compare to tug, Ger. ziehen, Zug, PIE *dewk- "to pull; to lead" (Note the accent on ḱ for *deyḱ- though). For the Anlaut we can compare *(s)teH- "stand, set" on the one hand and *deH- "do, put place" on the other, with various extenstions around *(s)te- (for stiff, etc. etc.). Arguably, a prefix *(s)- could fortify a coda *deH- to *(s)t- > *t-. I'm betting on the prefix reflecting "ex".
Further compare dyke, "ditch", *dʰeygʷ- ‘to stick, set up’; The difference should be as small as between Ger. "Zeugs", "Zeug" and "zeugen"; (saying so because for dyke we observe "Lithuanian diegti ‘to prick; plant’, dýgsti ‘to geminate, grow’"; cp. Ger. Erzeugnis, "produce"; Further, cogante German Teich "pond", Latin fīgō "to affix" imply that Ger. angelegt relates, which pertains to seed beds as well as to ponds, further to clothes and eventually to ships tied in harbor"). Thus, "ditch" does remind of the above mentioned "leave" as well as of Lat. "lego", or rather Ger. "legen".
And then some ...
All that's to say, it--das Deuten--is yet uncertain.