Need for derivative translations support
We need a way to group translation of the same language and only have small specification per country/flavour.
I propose that trytond tries first to pick a translation including country if there are none or it is empty then it tries to pick the translation from language only code.
On Pootle, the translators when translating for a country, will have to configure Pootle to show the language translation and so he will leave it empty if it is the same.
Also I think a cleaning will be needed for the current duplicate languages.