Gets even weirder in Finnish, because it's "kilpikonna". Someone in ye olde times just straight up translated the Swedish name. Got none of the Indo-European roots in sight, but it still makes sense. Vaguely toady creature that has shields!

(Only problem are the homonyms. "kilpi" also means registration plate, and "konna" also means "villain, thief". So every time some random person goes around nicking plates off cars, the journalists think they are very clever again, even when the joke has been made before numerous times. Poor turtles! They don't deserve this!)