Where does “so-” come from?
so- (Irish) comes from Old Irish so-, from Proto-Celtic su-, from Proto-Indo-European h₁su-, from Proto-Indo-European h₁wes- — good; to be cheerful, happy; to eat, to feast.
so- (Irish): very; X-able, easy to X
Ancestry of “so-”, step by step
| Step | Language | Word | Meaning |
|---|
| 1 | Old Irish | so- | good |
| 2 | Proto-Celtic | su- | good, well |
| 3 | Proto-Indo-European | h₁su- | good |
| 4 | Proto-Indo-European | h₁wes- | good; to be cheerful, happy; to eat, to feast |