Emoji are a language of their own, and the native speakers fit squarely within marketing’s Holy Grail demographic: Millennials. From press releases written entirely in emoji to an emoji-fied Bible, the characters are the go-to shortcut for professional communicators of all kinds who are eager to reach young people. The very fact that 2017 saw the release of an animated movie solely about emoji with personas validates any indication that the icons have moved beyond subjective interpretation. They are a universally understood language, and like all languages, this one has given way to cultural rules and linguistic phenomena.

An initial hurdle for proper emoji communication was that the icons look different on Apple, Microsoft, and Google operating systems, which means that users aren’t always seeing the same characters. Thought you were sending a toothy smile with smiling eyes? If you’re using an Android and the person you’re texting has an iPhone, he or she will most likely read it as a grimace. Researchers found that whether people understood the sentiment of certain emoji as positive or negative varied both within and across platforms.

The potential for emoji miscommunication goes beyond device disparities, however. Though many laud the symbols as universal, there have been misinterpretations from the start. The icons originated in Japan, and many have local cultural implications. U.S. users often interpret the “Person with Folded Hands” emoji, intended to convey a Japanese expression of apology or gratitude, as a symbol of praying, begging, or high-fiving.

Ironically, given these mix ups, 70 percent of users surveyed in August 2015 reported that their leading reason for using emoji is: “They help me more accurately express what I am thinking.” The second most common reason? “It makes it easy for other people to understand me.”

That’s certainly true sometimes, particularly for unambiguous symbols such as the original smiley face or the thumbs-up. And when used correctly, emoji do accomplish a number of functions. Linguistically, they add a level of emotion that often takes more time, effort, and space to express in writing – not to mention humorous visual puns. Linguists are discovering that users even adhere to new grammatical nuances that reflect spatial relationships.

Emoji-speak has also replaced the previous generation of online slang – phrases like “lol” and “hehe” – on social media. Facebook found that approximately 34 percent of laughter on the platform was expressed through emoji. The symbols are especially valuable on Twitter, where substituting one character for five can help a tweet fit within the 140-character limit. Emoji have also found a home in the workplace – some 76 percent of American workers admit to emoji use in the office, according to a study by Cotap, a mobile messaging company. Keith Broni, the world’s first emoji translator, believes that while sending emoji to your boss would have been inappropriate five years ago, they’ve become “indicators of emotional expression and an attempt to generate a sense of comradeship within a relationship.” Broni’s title itself speaks to role that the emoji has taken up in the workplace.

How should marketers react to the rise of emoji? Using the symbols to connect with Internet users of all ages remains a smart way for brands to keep up (and stay concise). However, the recent findings about the potential for emoji confusion should serve as a wakeup call for marketers to be judicious in their use of the graphics. Though a well-placed emoji can add emotional nuance and may resonate particularly well with sought-after young customers, brands have to beware of unintended interpretations.

For now, emoji should play a role in campaigns and communications, but marketers must be sure to tread lightly to avoid losing their message in an attempt to stay on trend.