I decided to give translating the game to Dutch a shot. I followed the steps found in the to no avail.

What I did exactly:

1. Copy
   Localization Template.csv
   to
   Localization.csv
   .
2. Removed the columns of all non-English languages from
   Localization.csv
   (I kept English to serve as a reference).
   
3. Added a new column for my language.
   
4. Translated a couple of texts and saved the file.

Now I expected to be able to select my language from the options menu, but I can loop through the whole list and I don't see it. Do I activate it in some other way?

I later also tried the following:

• Removed the columns 'English', 'desc', and 'type' as well (in that order, and I restarted the game between each removal to see if it helped).
  
• Renamed my language to 'English', to see if it would override the in-game English translation.

What am I doing wrong?