I've installed the Software Informer client but didn't find an option to change the language. My computer's main language is set to English, therefore the client will probably use this setting to display the menus, but if you change the language of your Windows and localization I believe the menus will also change to that language if it's supported.
Otherwise, open a support ticket on the Support page to find out more about the Software Informer client and its features.
