Comments:A Turk.-Mong. isogloss; not quite reliable, because in Turkic one has to suppose assimilative voicing (*dẹg- < *dẹk-). In Korean and Japanese the reflexes of the root could have merged with those of *tàk`u q. v.
Comments:Poppe 28 (Mong.-Tung.), Lee 1958, 113, АПиПЯЯ 19, 33, 292, Rozycki 128. In Mong. one would rather expect *č- in front of -i- as the result of palatalization of *t-; preservation of the voiced consonant may be due to the interaction of expected variants *čiwrin ~ *duirin. The root is no doubt a very archaic one; it is probably attested also in several common Altaic derivatives. Cf. PTM *du-dgu 'couple, spouses' = OJ t(w)otug- 'to marry' (*tub-tu-); PM *dab-ku- 'twice, double, layer' ( > Chag. tapqur, Evk. dapkur etc., see Poppe 1966, 195, TMN 2, 429, Doerfer MT 101), also reflecting a -i̯-less form like *tub-k`V-; PTM *ǯūpti (*ǯub(i)-pti) id.
Comments:Lee 1958, 113 (Tung.-Kor.). An Eastern isogloss. The Korean form is aberrant in several respects (-u- instead of expected -ɨ-, -t- instead of expected -r-, low tone instead of expected high), and one may suspect it in being borrowed < Japanese.
Comments:EAS 50, 150, KW 85, 439, Poppe 16. A Western isogloss. In Mong. we also have Kalm. dekǝ- 'to stick in; coire' (KW 85), which Ramstedt (ibid.) compares with the Turkic and TM word; if this were the true cognate, we would have to think that Mong. *čig, *čike is borrowed < Turkic (as suggested in TMN 2, 659). The poor attestation of Mong. deke-, however, raises doubts (so does the final -e in Mong. čike, hardly to be expected in a Turkic loanword), so the traditional comparison (Turk. *dik : Mong. *čike) might be the best solution after all.
Comments:The meaning 'base of a horn' attested in some Turkic languages is probably original and explains well the semantic development elsewhere ( > 'callosity'; 'forehead (of an animal)' etc.).
