VirtualDJ comes in various Languages (English, Spanish, Italian, French, German, Chinese etc). The translated sentences and words of VirtualDJ are included in internal language xml files, so not available at some folder by default.
If you wish to translate VirtualDJ to your language (in case its not one of the available), you can download the English xml language file from https://virtualdj.com/download/english.xml and save it as YourLanguage.xml at the Documents/VirtualDJ/Languages folder and then translate all the sentences you will find in the xml file which are enclosed with <SomeName><SomeName/>
Once the new xml file is created, the Language can be selected from within VirtualDJ Settings (Options->Language)
If you wish to share the Language File that you have created with other VirtualDJ Users, see here how to upload it.
See some Language Files uploaded by users.
Note : Use an Advanced Editor (like Notepad++ ) or an XML Editor and make sure it's set to UTF-8 encoding and not ANSI.