Installation instructions for Spanish language pack
  1. Download the language file locale.js.

  2. Open Windows File Explorer and type in the following adress:
    %LocalAppData%\Microsoft\Windows Sidebar\Gadgets

  3. Open the folder named "StreamPortal.Gadget".

  4. Create a folder inside "StreamPortal.Gadget" named "es-NI".

  5. Copy the language pack file "locale.js" to this new folder.

  6. Close the gadget or Windows Sidebar and open it again.

If this doesn't work you either did something wrong, or
Spanish is not the system language of your Windows user profile.