Where does “-??” come from?

-?? (Sauraseni Prakrit) comes from Sanskrit -इक, from Lithuanian -ikas, from Proto-Indo-European -iḱos — -y, -ic.

Ancestry of “-??”, step by step

StepLanguageWordMeaning
1Sanskrit-इकadjectival suffix; doer
2Lithuanian-ikas—
3Proto-Indo-European-iḱos-y, -ic
Every word from Proto-Indo-European -iḱos →Every word from Sanskrit -इक →Every word from Lithuanian -ikas →