Sisters who share secret language go viral—expert reveals how it works

Having a sister means growing up with a lifelong best friend who’s always there to chat, vent, and gossip. But it turns out that sisters share more than just wardrobes and a sense of humor, because as it turns out, they can also share their own language.

A new trend has taken social media by storm, revealing the unique and hilarious words and phrases that only sisters understand. Women young and old are taking to TikTok to share their own “sister dictionary” that no one else would possibly comprehend.

That includes Sarah Liguori, 26, from New Jersey who revealed the secret language she and her three sisters, Gabby, Katie, and Anna have created. After growing up in the same household, Liguori told Newsweek that they’re all “fluent in the lingo,” and it immediately puts a smile on their faces.

Examples of their sister dictionary include saying “I have a case of the uglies” when their hair or makeup doesn’t go right, or Liguori’s personal favorite is referring to something negative as “Les Mis.”

The phrases mean nothing to anyone outside the family, but it’s a special dialect just between the sisters.

Liguori said: “I think sisters are almost telepathic. You can read each other’s minds because you grew up the same way and have so many shared experiences. My mom always told us that no matter what happens in life, you’ll always have your sisters.”

As soon as she saw this trend on TikTok, Liguori was “so excited” and she instantly went to find Gabby so they could get involved. Her TikTok (@sarahligg) video has already gained over 1.3 million views and more than 153,000 likes in just a matter of days.

“The social media reaction has been so fun,” she continued. “We never thought this many people would laugh along with us, but people have been so kind. Commenters have said they love our sister dynamic and that they want a sister of their own.”

What’s the Secret to a Sister Dictionary?

While the trend makes for some hilarious clips on social media, linguistic expert Dr. Cindy Blanco told Newsweek that it signals a much deeper connection.

According to Blanco, senior learning scientist at Duolingo, a shared language is evidence of “shared social bonds,” so siblings who have grown up together can form these associations.

“We typically think of dialects as being the way huge regions or entire countries speak, but friend groups can show mini versions of this, like their own slang words for very particular meanings and pronunciations,” Blanco said.

“What we see among close friends and these words and phrases is the small-scale version of what happens with languages and dialects over time.”

This isn’t a new concept, as Blanco says that humans have long used shared languages to build alliances. “It’s an outward sign of a significant relationship—it shows that you know something special from those who don’t share or understand your lingo,” Blanco said.

How To Pick the Right Words

Just like the Liguori sisters, Chelsea Lefkowitz, 25, has also developed a quirky language with her sister Amanda, 30. They have been coming up with their own words and expressions for most of their lives, as Lefkowitz jokes that they’re now “instilled” into their everyday dialects.

But how do they pick which new words to add to their exclusive sisterly language?

Lefkowitz, from New York City, told Newsweek: “We shorten, lengthen, or re-phrase words that already exist. Some special words, like Nosetta (someone who’s very nosy) or Zengata (when your hair is a mess/in your face) were passed down from our lovely maternal grandmother, Mema, who is the original creator.

“With a shared background, it’s easy to develop inside jokes, references, and unique ways of communicating that only family members or besties can understand.”

Over time, the Lefkowitz sisters have added phrases like “Chilean Sea Bass” to their dictionary, meaning it’s cold outside, as well as “schoffing” when referring to someone who is shoveling food down.

They love having a way of communicating that’s personal and it’s now become “so instinctive” to them. Lefkowitz couldn’t resist adding to the trend as she shared her own TikTok (@chellefko and @amandapaige122) and she loves seeing other sisters relate. She’s continued sharing a whole series of videos revealing their sister dictionary (because they have so many words in it).

“We love our sister dictionary and we’re so glad others appreciate it as much as we do. Cheers to sisterhood,” Lefkowitz continued.

It’s a Deeper Connection Than Any Friendship

Like others, Grace Peck, 18, from Des Moines, Iowa, has loved seeing so many sisters reveal their secret language. It’s made her eternally grateful to have such a close bond with her sister Millie, and they too got in on the action by posting their own TikTok video (@grace.peckk).

“I think sisters just have a deeper connection, and I don’t know if it’s because we’re the same gender or what, but we just have a special relationship that I don’t share with anyone else,” Peck told Newsweek.

Many of the phrases they’ve formed have come from funny or memorable moments that they wanted to hold onto and cherish.

The social media response has been unlike anything Peck anticipated. She was inundated with comments from people wishing they had a sisterly relationship like this, which made Peck even more grateful for what she and her sister share.

“I love that the video blew up, but I’m even more grateful that I have a sister who I share this connection with,” she continued. “Sharing memories with her every day is something that no amount of likes can replace.”

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