A few years ago, the Government of Canada started trying to move toward plain language. Editors had received significant training and then transferred their knowledge to their internal clients. For agencies or departments that didn't have editors, or in situations where the editors were unable to effectively transfer knowledge, contractors were hire to provide training.
What they found was quite interesting. Convoluted language was often used out of a fear of sounding unintelligent. Why use a simple phrase when a big, complex word will suffice. There is an assumption that for products to get approved by senior management, it had to be filled with flowery language and words many people would need a dictionary to understand. The process seems to get reinforced when new employees arrived and were asked to write a specific document, be it a memo, policy, strategy, etc. The first thing they would do, would be to find an example of such a document and copy its style, thus perpetuating the problem.
What's worse, executives would approve the document, often making only minor changes to some of the simpler text or punctuation, avoiding the admission that they didn't understand what they were reading, not wanting to seem less intelligent than their staff. So, we had writers afraid of seeming unintelligent and therefore writing text that was above the comprehension level of management who didn't want anyone to know they didn't understand what they were reading. Of course, this is a generalization, but I experienced it first hand a few times.
After receiving training, staff still weren't applying plain language in their writing, although the text did become slightly more readable. Upon investigation, it was discovered that the behaviour was so entrenched that staff felt they needed permission from senior management to actually write in an intelligible manner. It took senior management to attend the training and speak to staff about the need for plain language before any significant change occurred. What made it easier for some was to explain the need as an accommodation for various disabilities internally and lower education externally.
While we are now seeing the results in content destined for public consumption, internal documents still suffer, as do the readers. Baby steps, I guess.
While this tool doesn't measure plain language andisn't intelligent enough to discern meaning in the text to discern whether it actually makes any sense, it's a good start.
I found another interesting tool: _http://www.online-utility.org/english/readability_test_and_improve.jsp
Gonzo