The fourth reason that makes English difficult is whether stress with the use of too much. Most people, therefore all efforts and I think it's difficult, tedious. Like a number of scientific subjects.
The fourth reason that English is difficult, it is a stressful learning overuse. Most people are so desperately trying to find it difficult and boring, like math or science.
The fourth reason that English is difficult is stressful and learning using too much. Most people are all effort and thought it was hard, boring, like math or science.