It is all known that people can easily distinguish one particular accent from another one. But we just do not know how to properly and rigorously express what on earth the differences are, apart from presenting some superficial segmental/pitch differences, say the /r/ sound differring American accent from British accent. Why is that?
Why do we still lack proper analysis tools to study accent?
Don't complain -- here's your opportunity to create some analysis tools and become famous, perhaps even the "father (or mother) of modern accent analysis".