The compound 'tart-tongued' is a vivid metaphorical construction from the 16th century. Its first element, 'tart', originally described a sharp, acidic, or pungent taste, a sense that persists in describing certain fruits or flavors. The second element, 'tongued', derives from the Old English word for the physical organ of speech. By combining them, the English language created a potent image: a tongue that delivers speech with the biting, unpleasant sharpness of a sour taste. This metaphor elegantly bridges the sensory experience of taste and the social experience of harsh criticism, perfectly encapsulating the meaning of sharp, caustic, or bitter speech.

Structure: tart (sharp) + tongued (speaking) - tart: From Middle English tart, meaning sharp to the taste. Likely of Old English origin, related to teart meaning severe, rough. Functions as an adjective describing a sharp quality. - tongued: From Old English tunge (the bodily organ). The suffix -ed forms an adjective meaning 'having a (specified kind of) tongue'. It indicates a manner of speaking.