Simple Sarcasm

Armando Iannucci writes in today's Daily Telegraph:

'... an eminent philologist was giving a seminar to some linguistics graduates outlining the results of his last five years' research. After an exhaustive examination of all the major world languages, he could find many instances of double negatives producing the same effect as a positive (as in "I found the lecture not uninteresting") but that amazingly, after years of searching, he was unable to come up with an example in any language of two positives meaning a negative. At the end, he asked the students if there were any questions and there was silence apart from one person at the back who just went: "Yeah, yeah." I don't know if the philologist is in work. I hope the student is.'