Language pack enables Site administrator to manage site in multiple languages. You’re not required to do any separate installation for to configure Multi-language.
Steps to Enable Multi Language in SharePoint 2010 Sites
Step 1: Download
Select the Required language pack from given link
Select required language and Press download.
Step 2: Install the language pack and Configure.
Just run the setup and after installation run configuration manager.
Step 3: Site Administration
Open the desired site and Go to -> site settings -> Site Administration -> language settings.
If you don’t have and extra language pack installed, language settings will not be available in Site
Click to setup language settings
Select the Required languages. In Given screen shot I have only language pack for Malay Language. After selecting your required language press Ok.
Select small icon on Login username and then you can see languages that you select in Site administration settings.
After selecting your required language you can see you site in different language.