A multilingual website is any website that offers content in more than one language. Examples of multilingual websites might include a Canadian business with an English and a French version of its site, or a blog on Latin American soccer available in both Spanish and Portuguese.
Usually, it makes sense to have a multilingual website when your target audience consists of speakers of different languages. If your blog on Latin American soccer aims to reach the Brazilian audience, you may choose to publish it only in Portuguese. But if you’d like to reach soccer fans from Argentina also, then providing content in Spanish could help you with that.
Google and Language RecognitionGoogle tries to determine the main languages of each one of your pages. You can help to make language recognition easier if you stick to only one language per page and avoid side-by-side translations. Although Google can recognize a page as being in more than one language, we recommend using the same language for all elements of a page: headers, sidebars, menus, etc.
Keep in mind that Google ignores all code-level language information, from “lang” attributes to Document Type Definitions (DTD). Some web editing programs create these attributes automatically, and therefore they aren’t very reliable when trying to determine the language of a webpage.
Someone who comes to Google and does a search in their language expects to find