Ok. I've done some digging. There is an issue is with the transformation. If you go to master page: there are 2 web parts language selector and language data source. Take a look at the transformation inside the language selector web part.
There is macro in transformation (and in the content before), that has the problem:
{%
cultureLocalizedName = GetResourceString("dancinggoat." + CultureCode, (CultureCode == "es-es") ? "es-es" : "en-us");
return
|(identity)GlobalAdministrator%}
and put resource string for LanguageName for all your cultures.
P.S. Th reason why you dont see resource string dancinggoat.en-us in localization because is Resource string priority.