German (Deutsch) for "Good day," a greeting.

It's as Patrick says. "Guten tag" means "hello" or "Good day!" In American English, we use other words from German such as "Gesundheit!" when someone sneezes or "kaput" when something is broken. I didn't know "kaput" was from the German language (spelled "kaputt") until a German acquaintance mentioned it when I said, "My computer went kaput." American English also includes a lot of words from the French language as well.

This is a joke, right?