Where does “*bliatua” come from?

*bliatua (Dalmatian) comes from Latin betula, from Gaulish bitu, from Proto-Celtic betwiyos, from Proto-Indo-European gʷét- — resin, gum.

Ancestry of “*bliatua”, step by step

StepLanguageWordMeaning
1Latinbetulabirch tree
2Gaulishbitu—
3Proto-Celticbetwiyos—
4Proto-Indo-Europeangʷét-resin, gum
Every word from Proto-Indo-European gʷét- →Every word from Proto-Celtic betwiyos →Every word from Gaulish bitu →