Where does “un deg wyth” come from?

un deg wyth (Welsh) comes from Welsh un, from Middle Welsh un, from Proto-Brythonic ʉn, from Proto-Celtic oinos, from Proto-Indo-European óynos — one; single.

un deg wyth (Welsh): eighteen

Definitions

  1. eighteen

Ancestry of “un deg wyth”, step by step

un deg wyth traces back through 3 separate lines of ancestry.

via Welsh un

StepLanguageWordMeaning
1Welshunonly; one; one, individual
2Middle Welshunone
3Proto-Brythonicʉnone
4Proto-Celticoinosone
5Proto-Indo-Europeanóynosone; single

via Welsh wyth

StepLanguageWordMeaning
1Welshwytheight
2Proto-Brythonicüiθeight
3Proto-Celticoxtūeight
4Proto-Indo-Europeanoḱtṓweight
5Proto-Indo-Europeanaḱ-sharp, pointed; sharp, pointed, edgy; sharp,...

via Welsh deg

StepLanguageWordMeaning
1Welshdegten; Soft mutation of teg
2Proto-Brythonicdegten
3Proto-Celticdekamten
4Proto-Indo-Europeandéḱm̥ten
Every word from Proto-Indo-European óynos →Every word from Proto-Celtic oinos →Every word from Proto-Brythonic ʉn →