https://www.youtube.com/playlist?list=PLjwA7yQNSjdxwmQWryMNlNQ4GbyrB1gvs

I say it in the 2nd floor tutorial video but switching to norwegian is only worth it if you can very good at either Neville skip or Malfoy skip. Missing or not doing those 2 strats loses around 40 seconds over US