I think examples of this you could focus on within the military side of flying is brevity terms. I.E. words like tally, contact, splash, etc. and what purposes they serve.
These structures I think are what make rapid comms possible such as getting instrument clearances, missed approach instructions, etc.
International controllers may be bad, but I think international pilots are just as big a threat as well. For example this video is a perfect example. This is a great funny example of communication issues.
That said I think you might have a hard time finding a focused scope given the wide range of points you put forward, and I would think mixing the radio communications syntax with accents/language barriers is a bad idea. This is because you are trying to do a scientific examination so having more than one variable at play makes it hard to form a cohesive argument. So I would focus on either the syntax OR the language barrier, but avoid the combination of the two. This is just my opinion, but I think it will make it easier to build a solid argument.