This thesis provides a comprehensive evaluation of the language selectors’ optimal placement on responsive design mobile and desktop multilingual websites. Drawing from a two-fold research approach (a detailed corpus analysis and usability user testing), the study shows that most language selectors assessed are located on the top right corner of web pages, for both desktop and mobile versions, and that users show a clear preference for the top position of web pages for language selectors. The findings of this study offer valuable insights for web designers, specializing in localization, to take into account the importance of the language selectors’ placement in improving the usability of multilingual websites. We believe that our study provides important insights for web designers to enhance the usability of multilingual web pages in Switzerland while taking into account users’ preferences with regard to language selectors.