QuARS is a tool for analyzing Natural Language Requirements – although it would be an exaggeration to call it "automatic".  The tool performs a morphological and syntactical analysis on plain text requirements and attempts to measure vagueness, subjectivity, weakness, and a few more.

Natural Language Requirements (NLRs) won’t go away any time soon – that’s why this kind of research makes a lot of sense.  But it’s unbelievable tricky to work with NLRs in an automated way.  There are three main approaches to deal with the richness of natural languge:

Restrictive: constrain the form of the NLRs, e.g. using templates.  Very convenient for the Requiremens Engineer, but not that nice for the stakeholder.

Inductive: This is mainly theory about writing styles, without going into detail on how to do things better.

Analytic: In this approach, we accept the NLRs, but provide feedback for fixing them.  These have the hightest chance of adaption, because they are the least invasive.  This is also the route of QuARS: Analyze the requirements and provide some feedback on how to improve them.

The biggest catch (in my opinion) is that many analyses require well-maintained dictionaries to be effective.  I wanted to try the tool out, but they didn’t provide a download link (or information about a commercial version, for that matter).  I wrote them an email, if I get an answer, I’ll update here.