Meaning: to sleep is a strong verb in the Germanic languages. While I'm quite aware that strong vs weak anything has very little bearing on modern English, this is still something that puzzles me.
Sleep and slept do show some kind of ablaut, but then where does the -t come from? Why was it added to the end of this verb? I know very little about the specifics of English etymology, and only really have the viewpoint of studying other Germanic languages.
Was it just something as simple as not wanting "slep" as a word and adding the -t made it easier to say/understand? Or just some kind of leveling to make it like wept, kept, etc.?