Where does “sono” come from?

sono (Ido) comes from Esperanto sono, from Latin sonus, from Latin sonō, from Proto-Italic *swonaō.

sono (Ido): sound

Definitions

Step	Language	Word	Meaning
1	Esperanto	sono	sound
2	Latin	sonus	sound, noise; pitch; speech; tone, character,...
3	Latin	sonō	—
4	Proto-Italic	*swonaō	—

sono — Etymology, Origin & Word History | Etymology Explorer