hay hi,
that' s a very good question.and your son is genius.just like mine.i have three sons 5, 4 and 1yrs.so i had the same situition with my 4yr old .he never pays attention what i 'm saying but he learns.and he 's better than my older one .i have used a lot of teaching method like tv computer.cooking playing singing.stories.flash card and most important thing complements.every second of the minute they need complement and your patience.i do not know how you are doing with your son but try to calm your self and just keep doing wht you are doing even if he is not paying attention untill you finishthe book or somthing .and just pretend that you have enjoy a lot .leave every thing there .and watch him if he will come to that place .it means he was listening to you .and he was learning that 's wht i did to my son .i was succeeded.now he is in preschool.he is enjoying and learning there very good.