Between the foot and the resonator, the side of the pipe containing the mouth is flat. A plate of metal or wood called a "languid", fixed horizontally here, blocks the airway, except for a small slot called the "windway" alongside the mouth. This allows air to flow as a sheet of wind directed towards the pipe's mouth. Flat pieces of metal or wood called "ears" may be attached to the sides of the mouth for tuning purposes, and a horizontal dowel called a "roller" or "beard" may be affixed at the pipe to ensure prompt pipe speech.