> If a computer's handling of a language can vary so drastically, imagine how the human brain must deal with expressing or receiving complex thoughts through these.

Orthography and language are not the same thing. Having a complex orthography has no bearing on processing complexity. If a language has a complex orthography, it may be hard to read and write, which are learned skills, but it won't be hard to speak and listen (which are naturally acquired skills given exposure to a language in the critical period).