Memorizing how to spell a word like "definitely" would be one of the worst possible uses of a language learner's time. What I was suggesting was aural training

Memorizing how to spell a word like "definitely" would be one of the worst possible uses of a language learner's time. What I was suggesting was aural training—learn to distinguish words such as "his" and "he's", to hear the differences between bat, bet, bit, bot, but, bait, beet, bite, boat, and boot, etc... Various idiosyncrasies of an orthographic system are far less important than being able to hear difference between the sounds of a language.