Rosetta Stone advertises itself as one of the more effective methods of teaching yourself a new language. The Rosetta Stone philosophy state that the easiest way to learn a language is through immersion, and for that reason the software proposes to help you acquire a new language the way you did your first: by immersing you in it, rather than having you actively study grammar rules as you would in a classroom setting. Rosetta Stone does this through increasingly complex language packs available for purchase from several online retailers.
Download your new language packs. The best place to purchase packs to update is directly from the developer, at rosettastone.com. They can also be purchased from other retailers, or downloaded as torrents from file-sharing websites such as mininova.com or isohunt.com. Be careful when downloading from anyone other than the developer: Rosetta Stone will not offer its warranty or customer service support on software that was not purchased through them.
Scan all downloaded files for viruses. If you opted to purchase the software through Rosetta Stone, you will not have a problem, but if you chose to get your software from a torrent site or a third party retailer, you should scan it before opening it on your computer just to be safe.
Install the language packs. Your download will include installers along with the actual language packs. You will need to install these first. You will now be able to right-click and mount the language pack images, which will open a new window. In this window, select "Rosetta Stone installation CD." Follow the simple instructions to install the language packs.
Click "Run Installer" to begin the process. When it is completed, restart your Rosetta Stone software. You will now have access to your new language pack in addition to your old ones.