Clean Blog Plone 5 Theme: no language selectors

I'm trying to customize my Plone 5 site and I found the following theme very beautiful:

However, when I switch from Barceloneta to Clean Blog the language selectors (either text or flags) do not show up any more and there is no possibility to switch from one language to another, unless by typing the language prefix in the URL.
If I access the @@manage-viewlets In Barceloneta there is a viewlet that contains the language selector:
The same viewlet is not present in the Clean Blog theme.
Thanks for your help.

@gianni2638 this sounds like a bug in the theme. It is possible that there is no rule set up to include that viewlet (or that some other rule inadvertently excludes it). If you know something about diazo, you might try making a copy of the theme and editing rules.xml to pick up the languages viewlet.

In any case, opening an issue in the package issue tracker would be a great way to report the problem to those who maintain that theme. If you have a solution, you can even make a pull request to fix it!