SharePoint is used around the world and is built with support for various languages using two distinct support concepts. The first concept is language Variations.
Variations may be utilized if your org is using SharePoint for a public-facing website and you require various pages within the website to be available in multiple languages. Variations facilitate the management and maintenance of content for different users. Variations can be based on different languages, countries, or regions. Variations can also be used to represent different brands or devices. If your org actually has affiliate orgs which are managed in a similar fashion, you can use SharePoint Variations to represent that content in a different way for different users.
The other concept is based on Language Packs. Language Packs are provided by Microsoft and allow you to use SharePoint in a different language. This means your entire user experience. Site navigation, Site menus, and the SharePoint Ribbon are all available in the selected language. SharePoint search also uses the language information. Users creating Sites have the option to select the default language of the site. SharePoint will automatically detect the browser language preference and react appropriately. Users may also select the desired language.