I get 'language file not found' error. how to fix it

By default, fm2 is set to use the English language. The language can be set by user, setting the options.culture option in the fm2.ui.config.json file.

Not yet implemented in fm2

Opening fm2 from CKeditor will pass the langCode variable to the fm2 through URL. langCode will overwrite all other settings.

The options.culture value corresponds to any of them contained in https://github.com/jlaustill/fm2/tree/master/app/lang