On a multilingual web site, how to forbid content edition at the top level?

I'm looking for a simple method to disallow edition at the top level of a multilingual web site, so only content of language folders can be modified (by non-admin users).

By changing the Modify Portal Content permission for the related content to Manager only?

Solution 1

Do not assign global roles.
Put all editors users in a group, assign the group to all language root folders (LRF) with the local roles needed.

Solution 2

This works with global roles:

Add a rolemap.xml to your profile where role contributor/ editor do not get any default add/edit/... permissions.

Create a workflow assigned to the LRF where editors regain those permissions.