'... that because you proceed toward mastery through a series of plateaus, so there's like radical improvement up to a certain plateau and then what looks like a stall, on the plateau, with the only way to get off one of the plateaus and climb up to the next one up ahead is with a whole lot of frustrating mindless repetitive practice and patience and hanging in there.’
The one who speaks is a teacher from the famous Enfield Tennis Academy and he establishes the analogy for the tennis training, how one must insist and keep training even when you think you aren´t progressing. I think the analogy also works for the language learning and for our topic today: the change of paradigm in the progress of science and the normal science concept.
It´s necessary to cross over all the plateau to get to climb to the next one. In Kuhn´s words: it´s necessary that normal science advances mechanically until a crisis appears. Then, there is a change of paradigm followed by another period of normal science