Readability plugin

[Lisa Howdin]

I'm hoping to manage content with multiple stakeholders in Confluence. To remind everyone to keep their content really simple, I'd love a widget on the side that calculates the reading level on what has been written. It would be great if it could identify passive language and provide realtime feedback about how to improve - something along the lines of: http://www.hemingwayapp.com/    or grammarly. 

Does something like this already exist?