You should add new language files with "_kn" suffix and copy translations of original strings to them. As I can see there is no Kannad Language translation as for today so you should translate everything yourself.
Original files to translate you can take from all .properties files in tomcat/webapps/share and some common files from /tomcat/webapps/alfresco. If you would like to join our translators community, then I can add Kannada Language as a target language in our project at http://crowdin.net/project/alfresco. We already exported all files to translate to this tool and you can just translate strings at CrowdIn. Language pack to install it to Alfresco will be built automatically.
