Where does “insla” come from?

insla (Romansch) comes from Latin insula, from Latin in, from Old Latin en, from Proto-Italic en, from Proto-Indo-European h₁én — in.

insla (Romansch): island

Definitions

Step	Language	Word	Meaning
1	Latin	insula	island; insula, a residential or apartment block...
2	Latin	in	in, at, on, upon, from; within, while in; into,...
3	Old Latin	en	in
4	Proto-Italic	en	in
5	Proto-Indo-European	h₁én	in

insla — Etymology, Origin & Word History | Etymology Explorer