Where does “нельзѣ” come from?

нельзѣ (Old East Slavic) comes from Proto-Slavic ne, from Proto-Balto-Slavic nē, from Proto-Indo-European né — not; no.

Ancestry of “нельзѣ”, step by step

StepLanguageWordMeaning
1Proto-Slavicnenot
2Proto-Balto-Slavicnēnot
3Proto-Indo-Europeannénot; no
Every word from Proto-Indo-European né →Every word from Proto-Balto-Slavic nē →Every word from Proto-Slavic ne →