I think you need to reaccess who your paying clients are. People that are so desperate to learn they'll try anything - expats in a new country for a job (or dragged along by a spouse), contractors dealing with workers and language barrier, esl teachers, travelers who want to be prepared to communicate with the locals, etc. Less fun, and more solution based advertising. I know I've seen Rosetta Stone ads highlighting it's use with diplomats and the like.