This looks for tandem sentences of very similar structure, on the theory that the first is a question and the second its parrot-like response. The differences between the two may correspond to a question particle, an answer particle (like "yes" or "no"), or some critical difference in syntax.

If you see nothing below, or nothing but a dogeared "X" below, it is probably because you need but do not have Java Runtime Environment 6, or 1.6 as it is also known. This is freely downloadable from sun.com.

A good little testbed, I have found, is the simple corpus
What do you think? You think whatEVER I think. And what do I think? I don't THINK, I KNOW.
Copy'n'paste it in, and be sure to try out all the delimiter, eliminate-dupes, case-sensitivity, and regular-expression stuff. It sure kept ME honest.

Late note: there may be a limit to how much text you can submit to this thing. See the bugs page for a little more commentary. Also expanded on in the bugs page: if there's nothing functional below, it may be because you lack the Java Runtime Environment, but it may also be because you're running this in IE8 on Windows 7.