Where does “kaksikymmenvuotias” come from?

kaksikymmenvuotias (Finnish) comes from Finnish kaksi, from Proto-Finnic kakci, from Proto-Uralic *kakta.

Ancestry of “kaksikymmenvuotias”, step by step

kaksikymmenvuotias traces back through two separate lines of ancestry.

via Finnish kaksi

StepLanguageWordMeaning
1Finnishkaksitwo
2Proto-Finnickakcitwo
3Proto-Uralic*kakta—

via Finnish kymmen

StepLanguageWordMeaning
1Finnishkymmenten; decade
2Proto-Finnickümmenten; decade, group of ten
Every word from Proto-Uralic *kakta →Every word from Proto-Finnic kakci →Every word from Finnish kaksi →