I know Objective C, C++, Java and have basic knowledge of C#. Of all these I'd rate Objective C as the easiest to learn and to handle. It's much more forgiving and easy on the programmer, and the syntax is trivial.

You seem to make a big case of the message passing syntax, but your example is very poorly chosen. Rather than 'performAction:withTwoParameters:' it should be 'performActionWithFirstParameter:andWithSecondParameter:' as are most Cocoa methods. Named parameters may seem verbose but they are much more readable than 'performAction(param1, param2)'.

If Objective C is a "large" language, I wonder what you'd call C++ or C#. Huge ? Humongous ? If you think Cocoa is large and complex, the C++ Standard Library or the Java library will make you weep.