Where does “insonnia” come from?
insonnia (Italian) comes from Latin īnsomnia, from Latin īnsomnis, from Latin in- -is, from Latin īn-, from Latin în, from Latin en, from Proto-Italic en, from Proto-Indo-European h₁én — in.
insonnia (Italian): insomnia; sleeplessness
Ancestry of “insonnia”, step by step