history’s secret languages

From knitted codes to whistled dialects, secret languages have taken many forms throughout history.

INVISIBLE INK Often tied to espionage, war and power struggles, invisible ink has a long and storied history. Take the humble lemon, for instance, which has long been used to transfer secret messages. A note written in its acidic juice will disappear when dry, only to reveal itself once heat is applied to either side of the paper. The ol’ lemon juice ink-plus-open flame trick was used to deliver messages between desert towns across the Arab world from 600CE, right up until World War I. Most infamous is the case of the WWI Lemon Juice Spies – a German immigrant and an English baker who joined forces to report British troop movements to the Germans using the innocuous citrus fruit. As decades passed, governments devoted more resources to creating new (fruit-free) ways of sending covert messages, many details of which are still hidden away in classified documents. What we do know is that spies have employed everything from high-tech chemicals to bodily fluids to conceal messages of political importance (as you may have learnt from the movies, saliva and semen show up under UV light). But these techniques haven’t always had such sombre uses – Ancient Roman poet Ovid encouraged folks penning love letters to express their desires in invisible inks, as well. LADY-ONLY SCRIPT For the women of 19th-century rural China, formal education was a rarity, thanks to a largely patriarchal society. And yet, in Jiangyong County in the Hunan Province, generations of enterprising women taught each other a special handwritten script. Nüshu (which literally translates to ‘women’s script’) was derived from Chinese characters, and allowed local ladies to write stealthy letters to one another if they married and moved away from home. It also equipped them to write poetry and, in some cases, their own autobiographies. The origins of the script are still hotly debated, but scholars all agree: men could not read it. Nearly all gents in the area knew of Nüshu’s existence, but simply did not care to sit down and learn. (Because who cares what women want to natter on about, right?) Apparently, Japan did – they banned the script during their invasion of China in the 1930s, for fear that it would be used to send covert messages to their enemies. In the latter part of the 20th century, girls stopped learning the lady-only language of their own accord, presumably due to growing rates of standard literacy across the country. ...................

HAND SYMBOLS Exclusive clubs and secret signals have always gone hand in hand. When it comes to flashing a tell-tale gesture, though, perhaps most notorious are those of rival Los Angeles gangs the Bloods and Crips. Two of the most active criminal groups of the ‘80s and ‘90s, hand signs became a recognisable part of each side’s identity – as important as the colour codes that differentiated a Crip (blue) from a Blood (red). ‘Throwing signs’ was a silent way to let those around you know where you were from and what you were doing in the area; conversely, flashing these finger formations at rival gang members signalled the start of a fight. Hand symbols also played an important role for the Hong Kong triads – aka organised crime syndicates – with different shapes representing a member’s rank in the group. Using only one hand, a triad member could communicate complex and super-specific hierarchies, such as ‘official who has committed a serious crime’, ‘ordinary member’ and ‘enforcer’. If you’re curious, there’s a whole canon of Hong Kong cinema that illustrates the inner workings of the triads – just don’t go flashing the hand signs on the street.

MICRODOTS In this current-day boom of privacy breaches and frequent online hacks, perhaps we could learn a thing or two from the microdots of yore. These feats of photographic innovation first came about during the Franco-prussian War in 1870, thanks to a photographer named René Dagron. At the time, important correspondence was sent via carrier pigeon – a vehicle that made sense for succinct, to-the-point messages, but certainly nothing detailed or secretive in nature. René’s brilliant solution? Create a teeny-tiny photo, laden with information and viewable only with a special magnifying piece of equipment. The pigeons were still used to transport the messages, but could now subtly carry dozens at once. At around one millimetre in diameter – approximately the size of a typographic full stop – the microdot was quickly snapped up as a wartime tool to keep uninvited eyes at bay. The trick was a special photographic shrinking technique that could reduce an entire document to a single dot – and, when feathered couriers weren’t appropriate, secret messages could be embedded within a postcard, ring or cufflinks. These were disguised as a simple gift, offered with an accompanying microdot reader that was cleverly hidden in a cigarette or fountain pen. ...................

WHISTLED LANGUAGES How to communicate with a friend who’s standing far across the plains? Don’t bother shouting – try whistling instead. Long before the advent of the mobile phone, folks have devised their own whistled languages to reach each other across great distances. In the tiny Greek mountain town of Antia, for instance, locals developed a melodic, bird-like whistle only they can understand – complete with grammar, vocabulary and full sentence structure. The language, Sfyria, dates back nearly 2500 years, when it was commonly used by shepherds across the valleys (perhaps to warn of nearby invaders). Meanwhile, halfway around the world, the Hmong people in the foothills of the Himalayas continue to keep their own whistled language alive – the shrill, piercing notes manage to cut through dense forests and across vast fields. At times, whistled notes are even used for courtship and seduction. Not in a creepy way, though – young couples have been known to create their own personal codes, deterring eavesdroppers and allowing them to hold intimate conversations in public. ...................

KNITTED CODE We all know the stereotypical image of a spy: a mysterious individual perched on a park bench in a trench coat, newspaper obscuring their identity. But in reality, during World Wars I and II, spies had a far craftier disguise: knitting. The domestic activity exited the home and became ubiquitous in public spaces, as women were encouraged to knit socks and hats for soldiers whenever they could. In fact, so innocuous was the sight of an older woman knitting in public, that Belgium hired these nimble-fingered dames to do just that while positioned casually near train yards. They observed and eavesdropped, creating coded stitches – a sequence of purls and gaps in a predetermined pattern – to communicate the goings-on of enemy forces. The knitted code would then be handed to a nearby soldier, under the guise of keeping them all rugged up from the cold. It may sound simple, but orbs of wool weren’t the only balls the crafty ladies needed – as espionage agents, they were bravely risking their lives. So, the next time you sit down to stitch up a woolly scarf, spare a thought for the stealthy crafters – and their fast-moving needles – that came before you.