Where does “xwerw” come from?

xwerw (Proto-Brythonic) comes from Proto-Celtic swerwos, from Proto-Indo-European swēr- — heavy.

Ancestry of “xwerw”, step by step

StepLanguageWordMeaning
1Proto-Celticswerwosbitter
2Proto-Indo-Europeanswēr-heavy
Every word from Proto-Indo-European swēr- →Every word from Proto-Celtic swerwos →