Multilingual Valid Path (Domain Access)
We use the Link Checker modules on our sites. This would scan all links and give a report back as to which are broken, if any. I don't see any reason why this would not work on any site, including multi lingual. 

Whether or not you use the module, you should be able to look at the code to get an idea of what functions and logic it's using to create similar functionality, if you're looking to do it programmatically.