Hello,
The easiest solution would be to use workflow on documents which you need to monitor for content changes. If you check
Send workflow e-mails in
Site Manager -> Settings -> Content Management, the workflow process will automatically notify members of the authorized roles that there was a document changed. This can be set for roles in
Site Manager -> Administration -> Permissions -> Content -> Manage workflow (notification e-mails will be sent to all users who belong to the role which has this property checked). After that, you can check those documents and make necessary changes like translating modified content, etc.
More information about workflow process and e-mail notification can be found in
Developer's Guide - Workflow and versioning.
Best regards,
Filip Ligac