Since version PRO 1.92 & Free 2.12 plugin was integrated with a Polylang plugin, so you could easily set-up public messages per language. Sections that can be translated marked as a “MultiLanguage text“.
To change the Current language please use the Admin Bar Switcher:
“MultiLanguage text” group
These sections can be edited per language.
“No MultiLanguage” group
Some sections marked with “No MultiLanguage” label can be edited only on the base language (usually English).
Even if you try to translate them on the non-base language – no changes will be saved.