Where does “Төлеген” come from?

Төлеген (Kazakh) comes from Kazakh -ген, from Proto-Turkic -gan — only}}.

Ancestry of “Төлеген”, step by step

Step	Language	Word	Meaning
1	Kazakh	-ген	Used to form past participles from verbs
2	Proto-Turkic	-gan	only}}