How to check what language is selected?

SkyTree

 I need this for my diary. Since I have 1 slot inventory based diary and add items/pages that have art and text as .png files. Thus when I change language I need to change those items/pages with another ones which have the new language.
So how could I check a new language is selected and call smth.?

Thanks

ChrisIceBox

The index number of the current language (starting from zero) can be read with:

int language = Options.GetLanguage ();