The action would require the installation of packages from not authenticated sources.

After I installed the ubuntu, and then i try to install the language package

System >> Administration >> Language Support

I got this error:

The action would require the installation of packages from not authenticated sources.

 

It seems that i have to install the untrust source. Ok, then this is the way to do it.

 

System >> Administration >> Update Manager

 

In the bottom of the window, there is a button "Settings", click it, in the tab "Ubuntu Software", I find that there is a selection "Software restricted by copyright or legal issues (multiverse)", then i uncheck it, re-try to install the language package, it done!

 

Have fun with Ubuntu!