In AskiaSurf, the source languages group of the options dialog allows you to specify which languages your projects are displayed in.
The group contains the following options:
Show source items in the current language of the campaign: If selected, source items will be displayed in the current language specified for the campaign. You can set the current language in the languages dialog (in the edit menu, select languages).
Show source items in the default language specified for each volume: If selected, source items will be displayed in the default language for each volume. You can set the default language in the languages dialog (in the edit menu, select languages).