One major technical hurdle to these readability calculations is that they rely on counting syllables, and Cocoa has no way of doing that for Mac; nor does Qt for Windows, I believe. There are some Cocoa classes out there (by other people) that do this, but they do it by splitting up words by vowels and then checking for lists of words and parts of words that don’t follow this crude rule. So, they are very rudimentary, won’t work well for half of the language, and even then only work with English. A syllable counter would need to be added at the franework (Apple) level for this really to be feasible.