Sets or gets the site's current display language.
Setting the currentLanguage property changes the site's display language.
The current page is reloaded in the newly set language.
Set the current language using a two-letter language code. The code must
represent one of the languages set to show on your site.
You can retrieve your site's languages and corresponding language codes using
the siteLanguages property.
Getting the currentLanguage property gets the two-letter language code
of the site's current display language.