Hi Fernão Lopes,
In OJS 2.3.3, there is now the option to allow submissions in multiple languages. If I remember correctly, Journal Managers can now specify which languages Authors can submit in. More information is available in a bullet here
. I don't think we currently have any plans on checking whether information has been added for mandatory fields for any *non-primary-language* locales -- that is, we'll always only check that the primary locale passes validation. Of course, if you can provide a use case we're more than happy to consider it as a feature request.