Thieves' Cant: D&D's Secret Language and the Real Argots Behind It

Thieves' Cant is the secret language of rogues in Dungeons and Dragons. It first appeared in the original 1974 rulebook, written by Gary Gygax and Dave Arneson and published by TSR. The mechanic gives rogue characters a private vocabulary for communicating about criminal activity, prices, dangers, and targets without being understood by outsiders.

The concept is not invented from nothing. Gygax based it on real criminal argots that existed in England and continental Europe from the 16th century onward. The most direct influence is "flash" language, documented in Francis Grose's "A Dictionary of the Vulgar Tongue" (1785), which cataloged the slang used by criminals, beggars, and the urban poor in London. Cockney rhyming slang and the German Rotwelsch argot contributed to the broader tradition Gygax was drawing from.

Dungeons and Dragons is now in its 2024 revised 5th edition, published by Wizards of the Coast. Baldur's Gate 3, the D&D-based role-playing game by Larian Studios, won Game of the Year at The Game Awards 2023 and received its final Patch 8 in 2025. Larian has since moved on to a new project returning to their Divinity: Original Sin series. You can experiment with the vocabulary using our Thieves' Cant Translator, which maps English words to their cant equivalents.

The original Dungeons and Dragons boxed set was published in 1974 by TSR, written by Gary Gygax and Dave Arneson. The Thief class was introduced in the first supplement, "Greyhawk" (1975), and Thieves' Cant was listed as one of the class's abilities. The idea was that a Thief could speak in a coded slang that other Thieves understood but guards, merchants, and ordinary people could not.

The mechanic evolved across editions. In Advanced Dungeons and Dragons (1977), Thieves' Cant was described as a combination of secret words, hand signals, and body language. In 2nd edition (1989), it was clarified as a non-written language passed orally among thieves. In 3rd edition (2000), it became a class skill that rogues could put ranks into. In 5th edition (2014), Thieves' Cant is described as a secret mix of dialect, jargon, and code that allows rogues to hide messages in seemingly normal conversation. The 2024 revised 5th edition keeps the same core concept with minor wording adjustments.

The Wikipedia article on Thieves' Cant covers both the real historical argots and the D&D mechanic. The game version is simpler than any real argot. It functions as a binary access control: you either know it or you do not. Real criminal argots are more complex, with regional variation, constant evolution, and partial comprehensibility even among non-criminals who have regular contact with the subculture.

What Gygax did was take a real historical phenomenon and compress it into a game mechanic. The Thief class was inspired by fantasy literature (Fritz Leiber's Gray Mouser, for example), but the cant ability was grounded in historical research. Gygax was a wargamer and history buff who read widely on medieval and early modern Europe, and the flash language tradition was part of that reading.

Francis Grose was an English antiquary and lexicographer who published "A Classical Dictionary of the Vulgar Tongue" in 1785. The book cataloged the slang used by criminals, beggars, sailors, and the urban poor in 18th-century London. A second edition, retitled "A Dictionary of the Vulgar Tongue," was published in 1788 and expanded in 1811. The Wikipedia article on Francis Grose documents his life and work.

Grose's dictionary is the primary historical source for what was called "flash" language or "peddler's French." Flash was the argot of the criminal underworld in London and other English cities. It was not a full language. It was a vocabulary of replacement words layered on top of English grammar, exactly like the D&D mechanic. A criminal could say "The cove has a rum bub" meaning "The man has a good drink," and only someone who knew the flash vocabulary would understand.

Some flash words from Grose's dictionary have survived into modern English. "Bilk" (to cheat or defraud) entered general usage. "Cove" (man) survived in regional dialects into the 20th century. Others are forgotten. "Bubber" meant a person who drank heavily. "Chant" meant a person's mouth. "Cant" itself meant the argot, and also meant to speak in it.

Flash language served two purposes. First, it allowed criminals to discuss illegal activity in the presence of outsiders without being understood. Second, it marked membership in the subculture. If you could speak flash, you were part of the community. If you could not, you were an outsider. This dual function, secrecy and identity, is exactly what D&D's Thieves' Cant provides for the rogue class.

Grose was not the first to document flash language. Earlier works include Thomas Harman's "A Caveat or Warning for Common Cursitors, Vulgarly Called Vagabonds" (1566), which described the language of beggars and rogues in Elizabethan England. Harman's work is one of the earliest English descriptions of a criminal argot, and it predates Grose by over 200 years. But Grose's dictionary is the most comprehensive and the most accessible, and it is the source most cited by later writers on the subject.

Cockney rhyming slang is the most famous English criminal-adjacent argot. It originated in the East End of London in the mid-19th century, primarily among market traders, dock workers, and criminal communities. The Wikipedia article on Cockney rhyming slang covers its history and structure.

The mechanism is simple. You replace a word with a phrase that rhymes with it. "Stairs" becomes "apples and pears." "Wife" becomes "trouble and strife." "Look" becomes "butcher's hook." Then, in a second step that makes the slang harder to crack, the rhyming word is often dropped. "Have a butcher's" means "have a look," but the word "hook" is gone, so the rhyme is invisible unless you know the full phrase.

This two-step obfuscation is what makes Cockney rhyming slang effective as a secrecy device. A listener who does not know the full phrase cannot work backward from the spoken word to the target word, because the rhyming connection has been removed. You have to know the code. There is no mechanical way to reverse it from the surface form alone.

Cockney rhyming slang differs from flash language in that it is a generative system rather than a fixed vocabulary. You can create new rhyming slang on the spot, as long as your listener knows the convention. This gives it a flexibility that flash language lacked. Flash words had to be learned individually. Rhyming slang can be improvised, though the established phrases are the ones that stick.

The connection to D&D's Thieves' Cant is indirect. Gygax did not model the mechanic specifically on Cockney rhyming slang. But the principle is the same: a vocabulary that is opaque to outsiders and learnable by insiders, used by a subculture to communicate privately. The Nadsat slang from A Clockwork Orange draws more directly on Cockney rhyming slang, as Anthony Burgess was explicitly influenced by it.

Rotwelsch is a German criminal argot that dates back to at least the 14th century. It is older than English flash language and Cockney rhyming slang, and it is still spoken in reduced form by some communities in Germany and Switzerland. The Wikipedia article on Rotwelsch covers its history and current status.

Rotwelsch is a mixed language drawing from German, Romani, Hebrew, and Yiddish. The Hebrew and Yiddish components come from the historical connection between Jewish communities and itinerant trades in medieval and early modern Europe. Criminals and beggars who traveled the same routes as Jewish merchants borrowed vocabulary from these communities, because the words were already unfamiliar to the German-speaking authorities.

The grammar is German. The vocabulary is mixed. This is the same pattern as flash language and Cockney rhyming slang: the host language provides the syntax, and the argot provides the replacement words. Rotwelsch words include "Bach" (river, meaning money or wealth, from Hebrew), "Schokel" (knife, from Romani), and "Galjan" (chicken, from Romani). The argot was used by vagabonds, traveling craftsmen, and criminals to communicate without being understood by town authorities or guild members.

Rotwelsch is historically significant because it demonstrates how criminal argots borrow from minority languages. The borrowing is not random. It happens because minority languages are already at the margins of the dominant society, and their words are already unfamiliar to the authorities. This is the same reason Nadsat borrows from Russian (an adversarial language during the Cold War) and why flash language borrowed from Romani in England. The pattern repeats across cultures and centuries.

The D&D Thieves' Cant does not specify which real-world argots it is based on, but the structural similarity to Rotwelsch, flash, and Cockney is clear. All of them are vocabulary replacements on top of the host grammar, used for secrecy and identity within a subculture. Gygax's contribution was recognizing that this historical pattern could be gamified.

Gary Gygax was a history enthusiast who read extensively on medieval and early modern Europe. His home town of Lake Geneva, Wisconsin, was also the home of TSR and the center of early D&D development. The Thief class and Thieves' Cant were products of his reading and his game design instincts.

The adaptation is straightforward. Gygax took the real phenomenon of criminal argots and simplified it into a game mechanic. In real life, flash language and Rotwelsch are complex, evolving systems with regional variation and partial comprehensibility. In D&D, Thieves' Cant is a binary ability: you know it or you do not. This is a necessary simplification for a tabletop game where the dungeon master needs to make quick rulings.

The 5th edition (2014) description adds a detail that brings the mechanic closer to real argots. It says that Thieves' Cant allows a rogue to hide a message in seemingly normal conversation. The message is not a separate language. It is a layer of meaning embedded in ordinary speech through word choice, emphasis, and coded phrasing. This is closer to how real argots work. A flash speaker in 18th-century London did not switch to a different language. They spoke English with replacement words and coded references that only other flash speakers understood.

The 2024 revised 5th edition maintains this approach. The mechanic remains a class feature of the rogue, and the description emphasizes the conversational embedding rather than treating it as a separate language. This is a better model of how real criminal argots function, even if it is still a simplification.

For players who want more depth, the Druidic Translator covers another D&D class-specific secret language, and the Deep Speech Translator handles the language of aberrations and mind flayers. Both are more fantastical than Thieves' Cant, which is grounded in real linguistic history.

Baldur's Gate 3 was developed by Larian Studios and released in August 2023. It is based on the D&D 5th edition ruleset and is set in the Forgotten Realms campaign setting. The game won Game of the Year at The Game Awards 2023, along with awards for Best RPG, Best Narrative, Best Multiplayer, and Player's Voice. It is the most successful D&D video game ever made.

Larian released Patch 8 in 2025, which was their final major content update for the game. The patch added new subclasses, evil endings, and additional content. Hotfixes followed in February and March 2026 to address bugs and balance issues. Larian has confirmed that they are done with Baldur's Gate 3 and are moving on to their next project, which returns to their Divinity: Original Sin series. This means no Baldur's Gate 3 expansion or sequel from Larian, though the D&D video game license may pass to another studio.

Thieves' Cant appears in Baldur's Gate 3 as a dialogue option for rogue characters in certain situations. The game does not make it a central mechanic, because a video game can handle secret communication through dialogue flags and skill checks rather than requiring the player to learn an actual vocabulary. But the lore is present, and rogue characters are recognized as speakers of the cant by NPCs who share the tradition.

The game's success has brought D&D to a wider audience than the tabletop ever reached. Over 15 million people have played Baldur's Gate 3 as of 2026. Many of those players have never rolled a physical d20. The cultural footprint of D&D is now larger than it has ever been, and Thieves' Cant, a mechanic that started as a note in a 1974 rulebook inspired by an 18th-century slang dictionary, is part of that footprint. You can explore the vocabulary with the Thieves' Cant Translator on this site.