Is there a way to completely disable the language url segment and rely only on cookies (epslanguage) to display the correct version of the content? Our customer doesn't want any URL changing.
Have you had a look at this page yet? Maybe it is a good starting point if you haven't... https://world.episerver.com/documentation/developer-guides/CMS/globalization/Globalization-scenarios/
That article doesn't really answer my question though. Our customer would like localized site without /en/ /es/ in every link. Is that something that can be done?
You may be able to write your own UrlRewriteProvider, but it seems like a lot of work for accompishing very little.
Here is the link for UrlRewriteProvider: https://world.episerver.com/documentation/Class-library/?documentId=cms/11/7763DC3