Where does “Serbish” come from?

Serbish (Manx) comes from Manx -ish, from Old Irish -as, from Proto-Celtic -assus, from Proto-Indo-European -ad-tus.

Ancestry of “Serbish”, step by step

StepLanguageWordMeaning
1Manx-ish-ish; -self
2Old Irish-asNominal suffix, used to form abstract ideas or...
3Proto-Celtic-assus
4Proto-Indo-European-ad-tus
Every word from Proto-Indo-European -ad-tusEvery word from Manx -ishEvery word from Old Irish -as