Hi Michael,
Yes the multi-languages approach in JR still needs to be improved a lot. So many things still need to be done.
I am a Joomla user and Joomla is very very far beyond JR when it comes to handling multi-languages. Many joomla template providers like rockettheme, joomlart etc have their own framework (gantry, T3 etc) which works almost like the JR site builder (with widgets and modules drag etc) but they are a little bit more advanced than the one provided here in JR and they are handling multi-languages pretty well.
Maybe the JR Dev team should learn from Joomla and their template providers how they handle multi-languages and maybe copy from them. They have done an awesome work. IMHO, even the translation approach in JR needs to be discussed again.
In Joomla and their templates (3rd party templates), I can build modules (widget) and module positions dragging things here and there. I can create menus and menu items and assign them to the language I want (en, es, fr, pt etc). but I can't do it here in JR.
About what you have said, I think it shouldn't be a big issue. Only the site interface should be translated. No need to translate the site content (audio and video). if there are many languages, the user is going to see all the songs but he/she can filter them with keyword searches or tags in a specific language. Many audio-video sharing sites like youtube use this approach.
Yes, replaying email requests that come in each of the languages is a bit challenging, but for someone who speaks all these languages, that shouldn't be a big deal.
Thanks
updated by @pch: 11/13/15 07:15:52AM