It all started on September 19, 40 years ago with emoticons, standard punctuation marks which were grouped together at a US university to represent facial expressions, most notably what came to be known as the smiley face - :-).

Since then, those combinations have evolved into the mini icons that we use so extensively today.

Modern-day emojis cover just about every area of life, from facial expressions to hand gestures and objects to the weather.

“They help to underscore how a statement is to be understood,” says linguist Erika Linz from Germany’s University of Bonn, whose research focuses on language and communication in digital media.

In face-to-face communication, the speaker’s facial expression, gestures and tone provide us with important clues about what they’re saying, whether something is meant ironically, for example.

When he implemented the emoticon at his Pittsburgh university in 1982, US computer scientist Scott Fahlman hoped it would help prevent misunderstandings in digital communication, which then took place via the school’s bulletin board system (BBS).

Back then, the system was mainly used by nerds with a tendency for sarcasm, Fahlman told the German Frankfurter Rundschau newspaper earlier this year. But many people struggled with understanding the intention behind the posts and wrote back in earnest, with real “wars of words” ensuing, Fahlman said.

From there, people started discussing the possibility of marking their jokes as such, in a debate that wasn’t serious at first either. But on September 19, 1982, Fahlman posted his suggestion, which would have implications so far-reaching he could have hardly foreseen it at the time: combining a colon, minus sign and bracket to depict a smiley face to indicate that something is meant humorously.

The researcher later said he had only intended the idea as temporary amusement for other users, but it soon took off and began spreading beyond the university, fuelled by the onset of the internet.

Today, emojis are not only used to indicate how a statement is to be understood, but are also increasingly replacing punctuation marks, says Linz. When a little icon is used instead of a period at the end of a sentence, for example, its meaning becomes “expressive”, according to the linguist.

Emojis also help to economise communication, with a thumbs-up symbol often used to quickly signal agreement, for example.

Conversely, the lack of emojis in a message has also taken on significance, as that is often used to convey a more serious tone. Many people have developed a sense for when to use emojis – and when it’s better to leave them out, says Linz.

Students of hers recently analysed the use of emojis by celebrities on Instagram, finding that actors and actresses tend to use them more often than politicians, for example.

However, Linz believes that the little icons will increasingly be used in formal communication in the long term as well. “The triumph of emojis is unstoppable,” she says.

Yet that won’t ever completely eliminate the risk of misunderstandings, the researcher says, as the meaning of an emoji can sometimes be ambiguous and people tend to use them in different contexts with different meanings implied.

From that point of view, maybe it was the simplicity of Fahlman’s original idea that helped the concept take off.