It was once dubbed "penmanship for illiterates" but emojis - the little symbols used to punctuate digital communications - have become so mainstream that 92 per cent of the world's 3.2 billion internet users admit to using them. Emojis have even been cited - successfully - in courtrooms from Israel to France as evidence of intent.
These icons range from the expressive - yellow cartoonish faces crying with laughter, looking angry, happy, sad and so on - to the figurative - a dancing lady in a red dress; hands clasped in prayer; an avocado; a pizza slice - to the scatological - see the smiling pile of excrement emoji for further elucidation. Now numbering more than 2600, they have become an essential part of modern discourse.
Their use is even spilling over into the workplace since they were loaded on to Apple users' desktops in 2011. One American study found that 76 per cent of respondents had sent the symbols to a colleague in a work email. Researchers at Ben-Gurion University of the Negev in Israel warn this week that work users should proceed with caution, however, as "smileys ... decrease perceptions of competence".
Not so, says the world's first "emoji translator". Keith Broni, 27, was appointed by consultancy firm Today Translations this year to iron out businesses' use of Unicode's pictorial language. When companies are unsure as to whether communications containing a winking face emoji will come off as cheeky, or just charmless, they give Broni a call. "You don't want to try to use the power of emoji and have it backfire," he says. "In interpersonal communications, [using them incorrectly] can be confusing or even contradictory."
For brands hoping the images will make them look relevant, failure to strike the right note "will look amateurish" and "like a corporate cash-in".
Broni is writing a guide to deploying emojis. "Five years ago, I would have advised avoiding emojis in work emails to your boss," he says. Today, things are different. "They're indicators of emotional expression, and an attempt to generate a sense of comradeship within a relationship."
Though he remains reassuringly opposed to kicking off work correspondence with a breaded prawn emoji, responding in non-verbal kind to a boss who has introduced emojis into the conversation is perfectly acceptable. Corresponding with a large chunk of words "can be read as quite cold", Broni adds. "A boss misinterpreting what you're saying as negative is even more embarrassing" than an ill-timed smiley face.
There are no-nos, of course: sending aubergines or peaches (commonly used to represent phalluses and bottoms); firing off too many emoji; or using one to communicate with an international colleague for whom the image might represent something entirely different (the thumbs up is offensive in Middle Eastern culture; the hand wave is deemed dismissive in China).
The practice still has its detractors, many of whom argue that emojis are a catalyst for the degradation of our language. Dr Arik Cheshin, assistant professor at the University of Haifa's Department of Human Services, co-authored a paper on the "dark side of the smiley". His study of emoji use in 29 countries surmised that sending an emoji to a new colleague can never end well, appearing too forced. "When you meet somebody for the first time and they smile, you don't assume they're being ingratiating," he said. "An emoticon is calculated."
Others posit that, far from dumbing us down, being well-versed in emojis is effectively the same as being bilingual, including Vyvyan Evans, a former professor at the University of Bangor and writer of The Emoji Code, who argues that flitting between the verbal and pictorial requires the brain to engage in the same degree of "code switching" required by someone who speaks two languages.
"Emojis are powerful tools," Broni says.
"They're a really valid form of communication that need to be taken seriously."
Excited about the moussaka you're making for dinner? Spell it out, don't use the emoji, which has become synonymous online with men's nether regions.
Crying with laughter
It was named Oxford Dictionary's word of the year in 2015, sparking fears that the end of civilisation was nigh. It's best left out of your work emails.
Nails being painted
One of the most misconstrued symbols, which is, according to many, a signifier of nonchalance.
Smiling through gritted teeth
Also best avoided at work. It means "you find a lot of things cringey or awkward", according to Broni.
Hands raised in celebration
Using too many of these may come off as overly excitable.