UIO+ should respond to the existing "system language" common term preference which is supported by the core GPII. They call it http://registry\\.gpii\\.net/common/language
UIO+ likely just needs to make use of the "defaultLocale" for Chrome language and the "locale" model value for the setting from GPII. We may need to expand the available localization of UIO to support this. And will need to consider how to update the context menu text.
NOTE: This won't allow UIO+ to translate web pages, but will allow UIO+ to be rendered/displayed using the system language.