Notes:

The context is that this is part of a talk given by Richard Stallman in Brazil, back in 2012. At first, he asked if the audience prefered him to speak in English or Spanish, it was 50/50, so he went with English. After talking for 20 or 40 minutes (I can't find a reliable account on this), the organizer of the event tells him to speak in Spanish because the audience overstimated their own understanding of English. Stallman, as anyone who was in his place would be, was not pleased with this, because time is limited, and he would have to do the talk again in order for people to get his point.