If you own a valid Vulcan.NET license, you are permitted to can distribute a certain set of assemblies (DLLs) with your application.
These assemblies are documented in the Vulcan.NET documentation and a list of these assemblies can be found in the redist.txt file located in the Redist folder inside your main Vulcan.NET installation directory.
The Vulcan.NET license does not specify that these assemblies must be used exclusively with applications compiled using Vulcan.NET.
In fact, the Vulcan.NET documentation includes an entire chapter titled "Using a Vulcan.NET Class Library From Another .NET Language", which describes how to use a Vulcan.NET class library with another .NET language and discusses potential issues you might encounter.
When compiling applications for the VO or Vulcan dialect, the X# compiler adheres to these same rules.
Some of the things that are written in this particular help file chapter do not apply to X#:
The documentation states that "no .NET languages other than Vulcan.NET understand the semantics of the USUAL or DATE types".
While this was likely true when the documentation was written, it is no longer accurate. The X# compiler now translates XBase types such as ARRAY, DATE, CODEBLOCK, FLOAT, etc., into the corresponding types found in the Vulcan.NET runtime assemblies.