Where does “s’” come from?

s’ (Manx) comes from Old Irish ís, from Proto-Celtic ɸīssu, from Proto-Indo-European pedsú, from Proto-Indo-European pṓds, from Proto-Indo-European póds, from Proto-Indo-European ped- — to walk, to step; to stumble, to fall.

Ancestry of “s’”, step by step

Step	Language	Word	Meaning
1	Old Irish	ís	under, below, beneath
2	Proto-Celtic	ɸīssu	under
3	Proto-Indo-European	pedsú	—
4	Proto-Indo-European	pṓds	foot
5	Proto-Indo-European	póds	foot
6	Proto-Indo-European	ped-	to walk, to step; to stumble, to fall

Words derived from “s’”

shegin
saa
s'loo

Every word from Proto-Indo-European ped- →Every word from Proto-Indo-European póds →Every word from Proto-Indo-European pṓds →