In French, you count from 69 to 72 like “sixty-nine, sixty-ten, sixty-eleven, sixty-twelve”. Then from 79 to 81 it goes “sixty-nineteen, four twenties, four twenties and one”. Then from 89 to 91 it goes “four twenties and nine, four twenties and ten, four twenties and eleven”.
It’s not consistently vigesimal, though. Twenty is “vingt”*, thirty is “trente”, forty is “quarante”, fifty is “cinquante” and sixty is “soixante” - so far all normal. The only ones where they go all vigesimal on us are 70 (soixante-dix), 80 (quatre-vingts) and 90 (quatre-vingt-dix).
*etymologically “two-tens”, if you go back beyond Latin: it’s from Proto-Indo-European *dwi(h₁)dḱm̥ti
In French, you count from 69 to 72 like “sixty-nine, sixty-ten, sixty-eleven, sixty-twelve”. Then from 79 to 81 it goes “sixty-nineteen, four twenties, four twenties and one”. Then from 89 to 91 it goes “four twenties and nine, four twenties and ten, four twenties and eleven”.
It’s not consistently vigesimal, though. Twenty is “vingt”*, thirty is “trente”, forty is “quarante”, fifty is “cinquante” and sixty is “soixante” - so far all normal. The only ones where they go all vigesimal on us are 70 (soixante-dix), 80 (quatre-vingts) and 90 (quatre-vingt-dix).
*etymologically “two-tens”, if you go back beyond Latin: it’s from Proto-Indo-European *dwi(h₁)dḱm̥ti