How can i have a custom theme created by myself for multilingual site? My website uses i8ln and it is configured to work with a large amount of languages. Using the page.tpl.php i managed to translate the website. But i had to create another custom theme for a specific path and the 404 page. So i created a page--node--23.tpl.php file and clear the cache. The file worked since the node i was trying to import the new theme was the node id defined when i created node/23. 
Now my problem is that i need to translate node/23 but when i click on translate and click save to save the translation another node is created and hence the page--node--23.tpl.php file is not used. How to set up drupal and able to adjust trasnaltion along with the custom themes???
Theming pages based on node id is not the way to handle this because you will have to copy each template to the corresponding translated nids. 
A better approach is to create content types based on differences (which can be different layouts as well). 
You can create a content type "404_page" for 404 pages in each language and create a template node--404_page.tpl.php to style them. This is all node specific.


There are also page specific overrides like: 

page--front.tpl.php  
page--user.tpl.php  
page--blog.tpl.php    

Edit: Some extra information on Theme hook suggestions can be found on the Drupal 7 Theme Hook Suggestions documentation page.