Unfortunately translating the string stored in cakephp is not enough to get working on the translation as this will cover only a small part of the application, namely error messages from the server, the few html pages like the login / recovery page (which will be soon migrated to JS).
The rest, and the biggest part of the interface, is split in two parts at the moment the “appjs” a javascript served by the server, and the web extension. We are currently in the process of merging these two and rewriting them in React.
Once this is done, hopefully by end of next month, we should be able to start tackling the bulk of work on the translations.