How can a multilingual website be implemented?

A recent need is to build a Web site in different languages based on countries in Europe, the Americas, the Middle East, Africa, Asia and Oceania. For example, European Spain, the site is in Spanish, the choice of Europe's Belarus, then this site is in Russian language, choose Asia's Japan, then this site is in Japanese display ...

How does one of these need to be implemented?

Through the online inquiry, there is a way I think it is better, but has not been achieved, temporarily first recorded, as the basis for reference, the subsequent implementation of the effect, you can easily paste code:

A domain multiple Languages page share a site

Or take the enterprise as an example: the site of the Chinese website is www.pageadmin.net/cn, the website of the English site is: www.pageadmin.net/en, Russian website is: Www.pageadmin.net/ru. Use the same domain name, and then according to the customer's language area to choose their own language, so not only to reduce the cost of the server, but also enrich the content of the site, easy to manage. And this is conducive to corporate Web site sub-domain can jointly enjoy the weight of the main domain name, if the main domain name exists for a long time, and has a fairly high weight, that for the sub-directory ranking, is also advantageous. Second, users and search engines can be based on these sub-directories, easily identify the different languages of the Enterprise website, this way to share a background, conducive to management and maintenance, is the current small and medium-sized enterprises adopt more ways.

How can a multilingual website be implemented?