It might sound strange but I am using alfresco as an academical course CMS. My sites are in the real world courses. I would like to know if it's possible to change in the whole Alfresco Share interface the value of the string "Site(s)" per "Course(s)".
Yes, it is possible. I have actually done this before for a client. It's a matter of finding all the places it is referenced, mostly it is in properties bundles, and changing it. It takes some work but it can be done.