You have to put your book under your pillow. The knowledge will magically go into your head while sleeping. Good luck!

i don't think there is any "lazy" way to learn a language. it takes a lot of effort... but things that help would be to learn basics (gretings/numbers/common phrases)... listen to songs in that language while reading the lyrics and then translating the lyrics... watch movies in that language with subtitles... keep practicing it... etc...

I like everyone's answers, but am compelled to add my response as well. There is no EASY way for LAZY people to learn a new language. If I were a mother of this LAZY learner and wish that he/she learns Japanese, I 'd ship him/her to a rural Japan where nobody speaks only but Japanese. LAZY or not, one must start communicating for the everyday necessities, and would learn important daily vocabulary pretty fast. However, it would take quite a while for a lazy person to up his/her overall language skills. Like ShakespeareRules wrote, laziness is the antinomy for motivation. I'd have to conjure up some motivation for the lazy child. Perhaps find a fantastic job opportunity in Japan for him/her, or maybe wait for him/her to fall in love with a Japanese who speaks only but Japanese. Or, perhaps like Harregarre suggested, wait for a miracle to happen. Finally, if nothing works, then I'd tell the lazy child to give up on learning Japanese (or any other languages).

If you really want to learn, then you have motivation. Motivation is the opposite of laziness. But like what was said earlier, there is no lazy way to learn a language. You have to put in a lot of effort. (Some people have to put in more effort than others, but that's a different story.)