When I searched for "lewis gompertz" I got at the top of results the English Wikipedia's page (https://en.wikipedia.org/wiki/Lewis_Gompertz), and at some point later down also the German Wikipedia's page (https://de.wikipedia.org/wiki/Lewis_Gompertz). I got this on both mobile and desktop with these settings: Country/Region as United States, Language as English, Fewer Results per Page is Off, query: https://kagi.com/search?q=lewis+gompertz
I did not expect to see German language literature in my results. Besides generally excluding other language results Kagi should especially exclude different language subdomains of the same site.