Mind Hacks has an interesting write-up of a study on overheard phone conversations, which tries to understand why someone talking nearby on a phone is far more distracting (and thus irritating) than two people having a face-to-face conversation.
The study suggests that it may be that hearing just one side of a conversation attracts our attention more as we attempt to guess what is being said at the other end. The human brain is very good at filtering out unwanted information, but to do this it must be able to predict the nature of this information. So an unpredictable one-sided phone call in the background gets our attention even when we don’t want it to.
The idea that this attracts your attention got me thinking about it’s possible application for learning languages. My main memory of first-year listening class was everyone struggling to concentrate on the boring dialogues being played. Perhaps this could be remedied by introducing one-sided dialogues, where we have to try and guess what the other participant might be saying.
Going further than concentration, it’s conceivable that the act of guessing half the dialogue would be beneficial to reinforcing learnt material and increasing fluency. Good speaking practice is very hard to come by, and certainly can’t be recorded for distribution. Maybe this method would have at least some of the benefit of real speaking practice.