Where does “flatten” come from?

flatten (Middle English) comes from Old French flatir, from Frankish *flattjan, from Proto-Germanic flatjaną, from Proto-Germanic -janą, from Proto-Indo-European -yéti, from Proto-Indo-European yé-, from Chichewa iye — he, she.

Ancestry of “flatten”, step by step

StepLanguageWordMeaning
1Old Frenchflatirto knock over
2Frankish*flattjan—
3Proto-GermanicflatjanąTo flatten, make flat
4Proto-Germanic-janąDerives denominatives from nouns and factitives...
5Proto-Indo-European-yétiCreates intransitive, often deponent,...
6Proto-Indo-Europeanyé-—
7Chichewaiyehe, she
Every word from Chichewa iye →Every word from Proto-Germanic -janą →Every word from Proto-Indo-European -yéti →