I am chuckling because the writer should have read the book's title. The sentence is unforgivably convoluted. The red part means: they have outlined different categories which attempt to "grasp" the diverse ways of speaking and listening. IMO, the word "grasp" makes little sense there. It sounds as if it should carry the "comprehend" meaning of grasp, but I am suspicious that they are using it to mean "elucidate", "demonstrate", etc. I have no idea how outlined categories can grasp diverse ways.Originally Posted by japanjapan
The red part consists of a relative clause inside a relative clause. The first clause: that the different categories attempt to grasp, modifies "ways", and its verb is "attempt". The second clause: (that) we have outlined, modifies "categories", and its verb is "have outlined".