Now it is much easier to build multilingual WordPress sites and run them with WordPress multisite install using Multilingual Press. You simply write your posts in your language and it automatically creates its duplication in the other sites and these new posts get interlinked and become easily accessible from the post/page editor screen – you can switch back and forth to translate them! Multilingual-Press is WordPress conform. This plugin doesn’t make any changes to the WordPress core and it doesn’t harm your website’s performance.
Install Multilingual Press plugin if you are using WordPress multisite network. After installation Network Activate it, then visit ‘All Sites’ and ‘Edit’ each Site and then select the tab ‘Multilingual’ to configure the settings for each Site. Following images will make it more clear: