Where does “brateńko” come from?

brateńko (Polish) comes from Polish brat, from Old Polish brat, from Proto-Slavic bratrъ, from Proto-Balto-Slavic brā́ˀtē, from Proto-Indo-European bʰréh₂tēr — brother.

Ancestry of “brateńko”, step by step

StepLanguageWordMeaning
1Polishbratbrother
2Old Polishbratbrother
3Proto-Slavicbratrъbrother
4Proto-Balto-Slavicbrā́ˀtēbrother
5Proto-Indo-Europeanbʰréh₂tērbrother
Every word from Proto-Indo-European bʰréh₂tēr →Every word from Proto-Balto-Slavic brā́ˀtē →Every word from Proto-Slavic bratrъ →