By default, PrestaShop is only installed with one languagetwo languages: the one used when installing the software. You can easily enable more languages: open the "Localization" menu, choose the ", and French. To manage the currently installed languages, go to the "Localization / Languages" page. It opens, presents you with a table of the available languages. English and French are installed by default, but you can import many more in the "Localization / Localization" page.
The currently enabled language(s) have a green check mark, while the others have a red "X". Click on any of the a green mark to disable the selected language; click on a red "X" in order to enable its languageit back.
You can enable all available languages if you think your shop needs them, but be aware that you will translate your content for all of the available languages: product name, description, tags; category name and description; static content (CMS pages); etc.
Only 2 languages are available by default. You can add more if you need. Find out how easily import many more languages in the "Understanding Local Settings" chapterLocalization / Localization" page, and then enable them in the "Localization / Languages" page.
Should you have people helping you with your shop, be they your spouse, friends or paid employees, you should make sure to create an employee account for each of them, if only to know who is responsible for which action. The other advantage is that you can give them specific profiles and specific access rights to the administration pages: for instance, you might not want everyone to have access to your statistics, your invoices or your payment settings.