Where does “sonvi” come from?

sonvi (Italian) comes from Italian sono, from Latin sūm, from Proto-Italic ezom, from Proto-Indo-European h₁ésmi, from Proto-Indo-European h₁ēs- — to be.

Ancestry of “sonvi”, step by step

Step	Language	Word	Meaning
1	Italian	sono	first-person singular present of essere; am,...
2	Latin	sūm	to be, exist
3	Proto-Italic	ezom	to be
4	Proto-Indo-European	h₁ésmi	first-person singular present indicative of...
5	Proto-Indo-European	h₁ēs-	to be

Every word from Proto-Indo-European h₁ēs- →Every word from Proto-Indo-European h₁ésmi →Every word from Proto-Italic ezom →