Go to Control Panel
Click on Date, Time, Language, and Regional Options
Click on Add other languages
Select "Languages tab" in the Regional and Language Options. Put a tick on “Install files for complex script and right-to-left languages (including Thai)
Click on the "Details" button of "Language tab" for installing Key board.
Click in "Add" button of "Text Services and Input Languages" dialogue box.
Select Malayalam [India] from "Add Input Language" list box. Click "OK"
Now the language bar appears in the status bar. You can select the lanugages by pressing Alt+ Shit .