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
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.