Good question, thanks for bringing that up
You will need to use Widget Logic Plugin https://wordpress.org/plugins/widget-logic/
You don’t really translate the widgets, instead you add another widget to the Footer Widget Area, with the translated info. and give it a logic.
Install widget logic plugin from https://wordpress.org/plugins/widget-logic/
Duplicate your widgets in the Footer Widget Area “If you have 4 widgets and are setting for English and French languages you would have a total of 8 widgets now, 4 in English and 4 in French”
Set the widget logic to ICL_LANGUAGE_CODE == ‘en’ and ICL_LANGUAGE_CODE == ‘fr’ for their respective widgets
Example screen shot (using English and Arabic)