what I mean is that once you want to access some API, the standard is C, so the headers you will get are in C. For example: windows.h. To do anything, either you have translated windows.pas, or you need to manually rewrite the function definitions. Another example: if you would like to access HongKong Exchange, you will receive a .so object and omni_api.h file, which is damn hard to understand, easier to use.
Pascal had a different calling convention so you can "just" write all your libraries in pascal.
As you say, calling out to other libraries would need a translation but ..... it's the same for python or many other languages. It would be a bump in the road but not a disaster.
That's why I said about freedom.