Where does “Isla” come from?

Isla (Finnish) comes from English Isla, from Spanish isla, from Old Spanish isla, from Vulgar Latin isula, from Latin Īnsula, from Proto-Italic enselā.

Ancestry of “Isla”, step by step

Step	Language	Word	Meaning
1	English	Isla	tributary to the Tay
2	Spanish	isla	island; block
3	Old Spanish	isla	—
4	Vulgar Latin	isula	—
5	Latin	Īnsula	—
6	Proto-Italic	enselā	—

Every word from Proto-Italic enselā →Every word from Latin Īnsula →Every word from Vulgar Latin isula →