Clauson (1972)
An etimological dictionary of pre-thirteenth-century Turkish
p. 694
köç-
(g-) ‘to change one’s abode, migrate’; with some extended meanings like ‘to be nomadic’, and metaph. ‘to die’ (i.e. migrate from this world to the next); homophonous w. 1 köç. S.i.a.m.l.g.; SW Osm., Tkm. göç-. Xak. xi sü: köçti: ‘the army (etc.) marched off’ (raḥila); the correct practice (al-aṣwab) with the unvoiced consonants (ḥurūfu’l-ṣalāba) is to convert the -d- in the Perfect into -t- to facilitate the pronunciation; the unvoiced letters are -p-, -ç- and velar and post-palatal -k-; but there is this difference about these letters that the correct usage is to form the Caus. verb (al-fi‘lu’l-wācib) with -d- because this is preferable (acwad) Kaş. II 5 (köçe:r, köçme:k; verse. It is only exceptional for this rule to be respected in the surviving MS. of Kaş.; for example the Perf. of tık- is shown as tıkdı:; it should be noted that -t- is not mentioned, although in this case the suffix is almost always -ti:/-ti:, and that -s- and -ş- are not described as unvoiced): KB 4814 (uluş), 6112 (köçütçi:): xiii(?) At. (this world is an inn) tüşüp köçgülük ‘the man who lodges there must travel on’ 177: xiv Muh. raḥala ğö:ç- Mel. 26, 10; 32, 13 ff.; Rif. 109, 117 (kö:ç-); al-raḥīl gö:çmek 36, 5; 122: Çağ. xv ff. köc- (‘with -c-’, sic) küç kardan ‘to set out, migrate’ San. 303r. 15 (quotn.): Xwar. xiv köç- (and, metri gratia, köçe-) ‘to migrate’ Qutb 100: Kom. xiv ‘to migrate’, and metaph. ‘to die’ köç- CCG; Gr. 149 (quotn.): Kıp. xiii raḥala köç- (so spelt) Hou. 37, 19: xiv köç- (‘with -ç-’) ẓa‘ana ‘to set out, migrate’ İd. 79; sāfara bi-ma‘nā rāḥa . . . wa akṯar mā yusta‘mal fi raḥl ‘to travel, go’, usually in the sense of ‘to migrate’ (safar et-/ket-/) köç- Bul. 47v. (the last six words follow the Turkish translation and are followed by köçti (repeated); they prob. refer only to köç-): xv köş- (sic) raḥala Kav. 9, 8; Tuh. 17b. 4: Osm. xiv ff. göç- ‘to depart, migrate’; metaph. ‘to die’; c.i.a.p. TTS I 315; II 441; III 301; IV 346.