Sentence:  A flue-pipe is one in which the air passes through the throat, or flue, which is the narrow, longitudinal aperture between the lower lip and the tongue, or <WSD>language</WSD>. ... The <WSD>language</WSD> is adjusted by slightly elevating or depressing it, ... 
Meaning of the word marked with <WSD> tags:  A languet, a flat plate in or below the flue pipe of an organ.