You can use Object Pascal in FPC without Delphi Mode. You cannot use Delphi Pascal in FPC unless you set the Delphi Mode On.

Object Pascal requires you to manage pointers etc.

[pascal]
Item := ^OtherItem
[/pascal]

While Delphi Pascal hides these pointer activities from you

[pascal]
Item := OtherItem;
[/pascal]

Object Pascal handles Objects in a similar method to C++ - one of the big reasons I dislike C++ so much. Delphi Pascal understands that passing a pointer to an object to another object means you want to pass a reference to that object and not actually pass the address of the object pointer to the other object.

This is the reason I like Delphi so much. The standard silly memory manageemnt mistakes are less likely as it already abstracts that away from the developer.

PS. My understanding is that Delphi is a derivitive of the pascal language now. It is now considered its own language and is no Longer considered pure pascal. (Just like Oracle PL/SQL is no longer considered SQL but is its own dirivitive)