Translating from the text of the article that accompanies the video, according to Josep Antoni Duran i Lleida "many times the majority language in the schoolyards is not precisely Catalan, it regrettably continues to be Spanish".
In the video we can see that his own "regrettably" -or were it the stunned faces of some on the parliament's benches?- makes Duran i Lleida lose track, as if he had noticed what he just said, and he tries to make amends, but makes it worse by defiantly underlining that expression and adding a parenthesis about Spanish being the "the language of the majority of the citizens" of Catalonia. This coming just a few sentences after describing the Catalan-only schooling system, that has been in place for some 30 years, as a success.
This is how reality and political aspirations collide, and rarely one can see that in such a condensed fashion. We owe this unique insight to the heat of the debate, that visibly has carried Duran i Lleida away to making some most visceral statements.
He is not a fascist, he's not even what goes for a nationalist hawk in Catalonia, but the idea he is defending here quite clearly is. Spanish, as he himself concedes, is the majority language "of the citizens", and it is an official language in Catalonia. So the citizens must be wrong if they use it. The system cannot be wrong: That's fascism.
Blown-out-of-proportion historical grievances and the totally undeadable idea that a Catalan cannot be wrong have brought us here, and there is no easy way back out.
As Duran i Lleida shows, the most human error is -regrettably- to dig yourself in even deeper.