I put my high-school Spanish to test this past week South of the Border. During a bunch of tourist activities (yes, that's me hurtling into a canyon), I re-discovered the power of looking like you know a language.
If a blonde or freckled American would attempt to communicate in Spanish, a guide would turn to me in bewilderment. I'd shrug and repeat the question, often word for word. Inevitably, the look of bewilderment on our host's face would disappear, and he'd rattle off an answer at full-speed.
Makes me wonder how preconceptions about appearance affect how I hear and understand voices. Do I tune in only when a person "looks" like they should be in the know? And do I ignore the words of those who don't?