The phrase speak with a forked tongue is considered to be an American idiom, but it is older than that. We will examine the definition of the phrase speak with a forked tongue, where it probably came from and some examples of its use in sentences.
To speak with a forked tongue means to tell lies, to not be truthful, to be deceptive. To speak with a forked tongue may be interpreted as saying one thing but meaning another. It is an insult to tell someone that he is speaking with a forked tongue, as it is the same as calling someone a liar. Almost all authorities believe that the metaphor of a forked tongue refers to the forked tongue of a snake. A snake’s forked tongue is also called a bifurcated tongue. The snake uses his tongue to activate his vomeronasal system or his sense of smell. The bifurcation allows the snake to have a three-dimensional experience of smell. The origins of the idea of the forked tongue meaning to tell lies is at least five hundred years old, and is probably derived from the image of Satan as a snake, as depicted in the Adam and Eve story in the Old Testament. In the story, Satan appears to Eve as a snake and talks her into sinning or going against the will of God. He does this by telling her lies and appealing to her curiosity and hubris. The expression forked tongue meaning speaking deceptively or lying is first seen in the early 1500s, predating the first English settlement in America by about one hundred years. The term speak with a forked tongue became more popular in the 1700s, at which time it was ascribed to a translation of a Native American idiom. It is possible that such an idiom existed in some Native American languages, though it is just as likely that it was the English speakers who gave the term to the Native Americans. For a culture that does not revile the snake, the term speak with a forked tongue may be interpreted as to speak with two tongues, which could indicate to say one thing and mean another. Related phrases are speaks with a forked tongue, spoke with a forked tongue, speaking with a forked tongue. Sometimes the phrase is rendered without the article a, as in speak with forked tongue. This is a reference to a stereotypical depiction of how a Native American spoke, especially in Western novels and films, and is generally considered offensive.
“Baudet speaks with a forked tongue,” said Volkskrant columnist Harriët Duurvoort, who is of Dutch, Surinamese, and African-American descent, when I talked with her in January. (The Nation)
As an independent, the only choice you got last election was between the lady with the Pinocchio nose and the white man who speaks with a forked tongue. (The Iowa City Press-Citizen)
When somebody says the Gilboa Snake rifle speaks with a “forked tongue,” it’s not an insult, but an accurate description of what happens when the dual triggers are pressed on this double barrel 5.56mm NATO semi-auto rifle. (Guns Magazine)