It looks to me like the dropdown is intended for 2 char abbreviations (looks like 5 chars might fit). I haven't looked at the code at all.
Assuming you don't need Afar, Abkhazian or Avestan (I don't even know where they are spoken ) :
What happens if you add
ae=>"the high road"
When scrolling down to Swedish, I think I have often felt it was easier to chose "aa" and change it by hand. (It is also possible to hit [S] 4 times until "se" is marked.) So I would also vote for a simple way to only include the langs being used.