That would be the EPiServerFramework.config:

<episerver.framework>

  <siteHostMapping>
    <siteHosts siteId="mySite">
      <add name="*" language="sv" />
    </siteHosts>
  </siteHostMapping>

</episerver.framework>

Thanks, that works half way. I'll get to the swedish startpage, but links in menues etc are english. When looking at PageData-objects when debugging, I can see that LanguageID and LanguageBranch are both set to "sv", which is correct, but LinkURL are all set to "&epslanguage=en", which even appear for pages that are not even published in english.

Are you upgrading a site from CMS 6 to 7 or is this a brand new site?

How do you render the menus? Is your master languagebranch for the startpage swedish?

This is a brand new site

Regarding to tha db-table "tblContent", the master language branch is English for most pages. Is there any way I can change this?

There is no official, supported way to change master language through the API but there are tools that help you tweak the database for EPiServer 5-6. (https://www.coderesort.com/p/epicode/wiki/LanguageTools)

I have not seen anyone do this for EPiServer CMS 7 yet...

What is your globalization node in web.config file?

<globalization culture="en-US" uiCulture="en" requestEncoding="utf-8" responseEncoding="utf-8" resourceProviderFactoryType="EPiServer.Framework.Localization.LocalizationServiceResourceProviderFactory, EPiServer.Framework" />

If this changed, when you go to http://MYDOMAIN/, you get the correct branch (that's how it works for me).

Tried globalization-settings too, no change at all