What programming languages can one use to develop iPhone, iPod Touch and iPad (iOS) applications?

Question

What programming languages can one use to develop iPhone, iPod Touch and iPad (iOS) applications?

Also are there plans in the future to expand the amount of programm

Answer 1

objective-c is the primary language used.

i believe there is a mono touch framework that can be used with c#

Adobe also is working in some tools, one is this iPhone Packager which can utilize actionscript code