Finnish breaks natural language processors
Finn here. There are countless memes about oddities of our language. The one I like the most is "kuusi palaa". It can mean;   the spruce is on fire
   the spruce returns
   the number six is on fire
   the number six returns
   six of them are on fire
   six of them return
   your moon is on fire
   your moon returns
   six pieces

Good luck for all implementing NLP :)