Install the app “Duolingo” and pick a language you would love to learn. From this day on, you will start the 4 weeks “language learning” challenge! You can choose between “casual” (5 min. a day), “regular” (10 min. a day), “serious” (15 min. a day) or “insane” (20 min. a day); every single one is okay, as long as you keep on repeating it every day. (Repetition is the most important for our experiment)