Take a look at internationalization:
http://www.yiiframework.com/doc/guide/1.1/en/topics.i18n
By setting the language parameter in the config file you specify what language to use. Echo your content with
Yii::t('langfile','message to translate');
For translations from the database look at:
http://www.yiiframework.com/doc/api/1.1/CDbMessageSource
Once you have everything in place. You can create CRUD operations for the translations just like you could for other any other database table.
Tutorials/More info:
http://www.pintarprogramming.com/23/Yii-internationalization
http://learnyii.blogspot.nl/2010/12/yii-setting-up-internationalization.html