Lütfen, which is "please" in Turkish. I just like the sound of it, and how it rolls off the tongue.

I find it very interesting that among words and phrases like "I am..." (minä olen), "you are..." (sinä olet), and so on, Duolingo also thinks it's important that I know the Finnish word for "wizard" (it's "velho," by the way).

"kasa" in Japanese is umbrella

"sus" which means "their" in español...