I18n: Update translation vi (57%).

43 translated messages, 32 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation nb (78%).

59 translated messages, 16 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation nb (100%).

75 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).