Rebuilding All Languages 
Path to Rebuilding All Languages:Languages & Phrases > Language Manager, then click [Rebuild All Languages].

This process regenerates all cached language data from the database. Generally this is not necessary. However, if you have edited the language information in the database directly, you need to run this process for your changes to take effect.
Running this process, even when unnecessary, will not harm your site.
User Contributed Notes: Rebuilding All Languages