How to add languages to PrestaShop
You can easily add more languages to your PrestaShop website. To do that you have to download the required language pack file (in .gzip format) from the PrestaShop official website. Once you have downloaded the file, you have to login to the admin area of your shop. Choose Tools -> Translations. Now, simply browse to the language pack file in your local computer and press the Import button.
The language pack will be installed in few seconds. Now you have to add it as a new language for your website. You can do this from Tools -> Languages. You have to upload a flag image for the new translation, a "no-picture" image (when the flag image can not be loaded) and enter the ISO and the language codes of the country. If you want to install Russian for example, you should enter "ru" in these fields. When you are ready with this step, press the save button, and the new language will be ready to use.