I like the dictionary idea. Not because it will cut down on spelling mistakes -- anyone who is making spelling mistakes in the 21st century doesn't care about spelling, period. Sorry. A dictionary won't help. If you change something else, make spelling an emphasis of your class (which is a sad waste of time when you only have so many weeks to teach poetry and plays and beauty), then perhaps. Rather, the percent of your students who actually do look up words on their phones would benefit from looking them up in a dictionary instead. When you flip through a dictionary, your eyes wander. I will never forget the word 'epigone', because it's one of the "edge" words in the OSPD Scrabble dictionary. Every time you open a dictionary you learn an extra word or two, by nature. Hell, make them play Scrabble. Seriously.