You sift the surrounding air for sound wave remnants of recent conversations to discern passwords or other important information gleaned from a conversation, such as by guards on a picket line. The spell creates a cloud of words in the caster's mind, assigning relevance to them. Selecting the correct word or phrase is not foolproof, but you can make an educated guess. You make a Wisdom (Perception) check against the target person's Wisdom score (DC 10, if not specified) to successfully pick the key word or phrase.