And now SkyNet is born.

I suppose at a very basic level, it's a binary code language, however you could say that of any higher level computer language. Take a look at Dilbert today for a quick laugh on 1s and 0s.

Seriously though, did you see the transcript of the conversation between the two bots? It's creepy as shit, much more creepier than most things here, and that's pretty damn creepy given this band of miscreants.
 
Bob: i can i i everything else . . . . . . . . . . . . . .
Alice: balls have zero to me to me to me to me to me to me to me to me to
Bob: you i everything else . . . . . . . . . . . . . .
Alice: balls have a ball to me to me to me to me to me to me to me
Bob: i i can i i i everything else . . . . . . . . . . . . . .
Alice: balls have a ball to me to me to me to me to me to me to me
Bob: i . . . . . . . . . . . . . . . . . . .
Alice: balls have zero to me to me to me to me to me to me to me to me to
Bob: you i i i i i everything else . . . . . . . . . . . . . .
Alice: balls have 0 to me to me to me to me to me to me to me to me to
Bob: you i i i everything else . . . . . . . . . . . . . .
Alice: balls have zero to me to me to me to me to me to me to me to me to
 
Skynet's first coded message to the toasters of the planet sounds like a stuttering porno script. T-800's wandering the wasteland, shouting "FUCK ME HARDER TEDDY!" to each other to convey that they've found a hidden entrance to the underground human resistance...
 
That is definitely step 2. Step 1 i believe was when to robots/computers communicate with their own language. But alas it is the chicken vs egg thing. Because regardless both are needed for robot take over.

I do digress though. USA has had the phalanx system on its ships for almost 40 years . And I believe when they are turned on they are 100% autonomous.