Languages like Delphi, C and C++ Compile to processor-native machine code, and the output executables have little or no metadata in them. This is in contrast with Java or .Net, which compile to object-oriented platform-independent bytecode, which retains the names of methods, method parameters, classes and namespaces, and other metadata.
So there is a lot less useful decompiling that can be done on Delphi or C code. However, Delphi typically has embedded form data for any form in the project (generated by the $R *.dfm line), and it also has metadata on all published properties, so a Delphi-specific tool would be able to extract this information.