For a customer of mine, I recently worked with the new template TeamRoom 8.5.3 XL available with Lotus® Domino Designer 8.5.3 Upgrade Pack 1 and based on the XPages Extension Library.
I activated the Localitazion options and I translated the Xpages part for the italian language.
Now the application recognizes automatically the italian language (from the web browser settings) either on the web either on mobile devices.
I think the new TeamRoom template is a great application to start workinkg on the XPages, but the localization availability is a must for a real case.
Here the link with the translation and some notes with instructions: Italian language for the TeamRoom 8.5.3 XP application (4649)