How can I add help tips on each page, like a sliding panel?
It sounds as if https://drupal.org/project/popup may be suitable for for your needs.

You could create a block with various contexts (your translations / page) and then use this module to display the block (using sub module 'Popup Block') on each page when the user requests it, by rollover or click or whatever you choose.

The module is mature, widely used, has a recent version and has documentation provided.