Where does “lagh” come from?

lagh (Old Swedish) comes from Old Norse lág, from Old Norse leggja, from Proto-Germanic lagjaną, from Proto-Indo-European legʰ- — to lie.

Ancestry of “lagh”, step by step

Step	Language	Word	Meaning
1	Old Norse	lág	a felled tree; log; lying tree
2	Old Norse	leggja	to lay, place, put; to make, build
3	Proto-Germanic	lagjaną	to lay, to place in a resting position
4	Proto-Indo-European	legʰ-	to lie