Where does “sonreir” come from?

sonreir (Old Spanish) comes from Vulgar Latin *subrīdīre, from Latin subrideo, from Latin sub-, from Proto-Indo-European upó, from Proto-Indo-European h₃ewp-.

Ancestry of “sonreir”, step by step

Step	Language	Word	Meaning
1	Vulgar Latin	*subrīdīre	—
2	Latin	subrideo	I smile
3	Latin	sub-	sub-
4	Proto-Indo-European	upó	under, below
5	Proto-Indo-European	h₃ewp-	—

Every word from Proto-Indo-European h₃ewp- →

sonreir — Etymology, Origin & Word History | Etymology Explorer