Use Drupal. Go to drupal.org and drupal.in

I second that.. (IF the site you are designing is a fresh one, and can easily fit into a CMS like drupal). I had used its i18n once, is straightforward.

If this is for Indian languages, you may also check joomla, has more indic translations of the core interface.

These use an internal mysql database, but you also have several caching options to tune for performance.