Why is the 's' in Island mute in English?
The “s” in island is mute because of a spelling mistake in history: The word comes from Old English ī(e)gland (literally “water-land,” īeg = island, land = land). There was no “s” in it. In the Middle Ages, scholars tried to connect it (wrongly) with the Latin word insula (island). To make it look more “learned,” they inserted an s into the spelling. The pronunciation, however, stayed the same — without the s . So the “s” is there only because of etymological confusion, not because it was ever pronounced.