Let me give an example what different student background and learning environment will impact the learning process. I know very little English when I emigrated to US when I was 13. I started high school after 6 months in the US. The school had no Chinese speaking teaching staff( Mandarin is my native language). Since I do not know much English to begin with. I don't think anyone can teach me English using what Author proposed. I built up my vocabulary one word at the time until I know enough word to understand young adult novels. Reading many young adult novels helped to increase my vocabulary quickly and I was able to catch up within 3 years and managed to graduate from high school and enter University.
My English deteriorated after I have been back to Asia for 20 years but hopefully I get my point across.