Which language is best suited for communication with computer systems and AI

All natural languages have their share of irregularities; I don't think there would be much to choose from between them. See Steve Pinker's <i>Words and Rules</i>, then an introductory linguistics text on syntax to get a more systematic view. We never really notice the complexities of language until they are pointed out to us, because our minds are designed by evolution to handle (or generate, if you prefer) language. There are still many problems in formalizing even relatively straightforward syntax of everyday language.

That's a really interesting question. I remember one time when I actually started to design a new spoken language which could be understood by machines. Didn't get too far with that though.