A multi-lingual website is a website where the content is written in more than one language. The information displayed in different languages is often the same, but maybe tailored for different audiences.More than 30% of the visitors on an average website come from search engines. Almost all the searches are done in the native language of the searcher. If your website has no content in their language, they will never even see your site in the results.
The first thing to get right when working with multiple languages on a website is making sure the language is identified in the code of the page. Next,you will need to choose the primary language for your pages. This is the language the majority of your content is written in. For example if your page is predominantly written in English then your primary language should be set as English. Once the primary language of your pages has been chosen, you will need to find the language code which corresponds to that language.
The majority of web pages use a single language at a time, however there maybe occasions when you want to include a language other than the primary one on your pages.