Hi,
I might be dumb in asking this. But, didnt want to waste my effort in recreating an already existing one.

Is there any kind of language/syntax framework for interacting with a system?

Like system level commands such as

system shutdown
mail check/compose/open
open firefox
screen brighten/dim/activate/switchoff
window minimize/maximize/etc..
desktop next/previous/one/two/...

and application level (context sensitive) commands like

page close/reload/back/forward (firefox)
save now
save as
etc.

I want to create an interaction layer to the system that can be used in all platforms. This can then be used in conjunction with gesture recognition, voice activation and certain shortcut sequences.

What do you mean with all platforms ?
All the existing OS that is quit a lot.
In some OS a works with in the past you can create as we call it a alias
It is a system command that means something to me or all other users .
It just how you make it .
As a example now = shutdown now and so on

Not at the level you are talking about. What you ask for is basically an IA controlled device (aka, robot, like in star wars ) that can deal with all the imaginable machines, oses, application frameworks and programming/scripting languages.

There's no such thing at all. Some of the stuff you talk about is very OS dependent, like acpi stuff (shutdown, etc). Some other stuff is very tied to the concrete GUI, like the max/min stuff. At most, you could do some kind of desktop-level daemon to achieve this on a reasonable number of desktops/wms (those respecting the EWMH standard). But this will only work on those wms supporting that (I know nothing about windows and mac stuff, in linux most of them do to a certain degree at least).

In which regards app-level interaction, it's only possible when there's a common infrastructure in the form of a inter-app communication system (corba, dcop, dbus...). Nothing standard that will work on all the OSes.

Being that said, you might have a reasonable degree of success if you concentrate yourself in a given desktop. I'd suggest using kde4, and developing your solution on top of it. The good part about it is that it runs on linux, bsd, mac and windows. All the kde applications can communicate with each other, and you can have a very high degree of control via dbus. It's the only solution (viable one, I mean) that comes to my mind.

Completely OS/arch agnostic solutions are not viable nowadays for your purpose. So, I suggest looking for the most portable framework, which, right now, is kde4. It's not going to be an easy walk, in any case.

Some functions are available through shell (shutdown, mail, open firefox).
Application-dependant commands might be available if application supports scripting.
I do not know about layer that allows WM-independant manipulation of windows/controls (maybe there is one, of course). To me it looks like this thing will need to be implemented by hacking any major desktop.
I recommend you to ask kde or gnome developers about this.