- What cute nicknames do you call each other?

- We both call each other Squish.

- Yeah.

- Oh, that's a new one.

- It was one of the first stuffed animals I got her.

It was like a little octopus.

- It was like a Beanie Baby.

- Yeah, a Beanie Baby.

- His nickname was Squish.

- My partner, for some reason, I always used to call him Boo.

Say I love you, Boo.

- My Skoosh, my Squishy.

- There's pyaar there's mahabat there's jaan, there's ishq - K.G.

Griffindor, Griffy, Little Griffy Boo-Boo.

- Tootie Butt.

- Tootie Butt?

- I call him Dad and he hates it.

I'm your husband, I'm not your dad.

(Dad laughing) - Why do we use such unusual words for the people we love?

From Kitty to Cutie, two thirds of American adults refer to their romantic partners by a pet name, and we've been doing this for a long time.

"The Historical Thesaurus of the Oxford English Dictionary" traces terms of endearment, in the English language at least, over 1,000 years.

While old-timey pet names, like Heartikin and Lamb Chop, have come and gone, Darling, which appears in written records as early as 888 CE, is one term of endearment we still use today.

But where do all these pet names come from?

And why is it so tempting to call our partners My Sweetest Little Pumpkin Pie instead of using their actual name?

I'm Dr. Erica Brozovsky, and this is "OtherWords."

(funky music) - [Narrator] Otherwords.

- What did your parents call you when you were growing up?

- Weeza.

- I grew up being called Kiki.

- Andy, Drea.

- Like the family name, they call me Cong, which is, which means smart in Chinese.

- Cong 'cause they think you're smart.

What other kind of?

- They hope I'm smart.

(interviewee laughing) - That was a wish.

- That was a wish, yes.

- A lot of our common terms of endearment are using words for things to describe people.

Linguists note that many of these terms of endearment fall into one of these categories.

(joyful music) (graphics popping) Any other nicknames that you all have?

- Curry.

- Yeah.

- And where did that come from?

- Her name's Carrie.

- My name's Carrie, and it just kind of morphed into Curry.

- I get called Peanut a lot.

- Sugar Pie.

- Honey, Sweetheart.

- My Little Chicken Nugget.

- Muffin, Sugar Plum, Baby Cakes, Honey Bun.

There's an endless list of desserts you can call your beloved.

It's also a cross-cultural phenomenon, from Arabic's Asal, meaning honey, to Japan's Tamago gata no kao, meaning egg-shaped face.

- So like Gulab Jamun is like an Indian sweet.

It's like a little brown, like sugary sweet, which is really, really good.

But sometimes when you have like a little boy, and like he has his cheeks, and then you'll say he's like a little Gulabu 'cause he like has the little cheeks.

- One of the earliest edible epithets is Sweetheart, which shows up in middle English texts as early as 1290.

However, it would take over 500 more years to show up on a box of Valentine's candy.

- My name like, Neil, it means blue in Hindi, and my middle name means mango.

So some people call me Blue Mango.

- You love mango.

- And I love mangoes too.

- Who doesn't, truly?

(graphics popping) There's a lot of crossover between food-related pet names and another popular category, plants, think Pumpkin Pie or Mon Petit Chou In French, which speakers say translates either to my little cabbage or my little cream puff.

- My cousin would go by Meng Meng.

Meng is like sprouting, like when spring comes, everything starts to sprout.

So meng is that action, so he'd go by Meng Meng.

- But using a vegetable as a term of endearment likely came later than nicknames like Honey or Sugar.

Pumpkin first shows up in descriptions of the American dialect in 1900, gaining popularity through the mid-century when, along with Sweetheart, Peaches, and other pet names, it picked up a sarcastic or condescending usage as well.

- I love you, Pumpkin.

- [Pumpkin] I love you, Honey Bunny.

(joyful music continues) (graphics popping) - Do you have a nickname?

- What do we call you?

- Monkey.

- Big Cat.

- Mama Bear.

- A third category of pet names is literally pets.

Animal names like Kitten and Lovebug are popular nicknames today, but in the late 1800s, you might've called your lover a Prawn.

Thai speakers have their Chang Noi, or little elephant.

And German partners might call each other Mausebar, because referencing just one cute animal wasn't enough.

And while we've covered Shakespeare's linguistic creativity before, linguist Julia Landman notes that he was also prolific with pet names, sprinkling animal-based terms of endearment, like Dove, Ladybird, and Lamb, throughout "Romeo and Juliet" and "Hamlet."

What nicknames did your family call you?

- Over the years, I've been everything from a Sue, to a Susie, to a Sue-Sue, to a Doo-Doo.

- My family calls me Ren-Ren, and I think it's a very Filipino thing to double name like that.

- My mom calls me Mijita, which means daughter.

(gentle music) (graphics popping) (teapot whistling) - Many terms of endearment fall under the category of diminutives.

Instead of standalone words, diminutives are affixes added to the beginning or end of words to connote smallness or cuteness.

Every language has their own unique diminutives.

There's ito and ita in Spanish, ette or lette in French.

English has diminutive prefixes like mini, as in minifridge or miniskirt, as well as suffixes like ie as in plushie or puppy, and ling as in duckling or darling.

- So my mom is from Italy.

She used to call me Bellina Piccolina.

Bella means pretty or beautiful.

Ina is a diminutive that's appended onto the end of a word to make it small.

And then piccola is small.

And then she added ina also onto the end of piccola.

So I guess if you were like literally translating it, it would be small, small, small beauty.

- In addition to indicating smallness, diminutives can also give speech an affectionate or familiar tone.

If you called your mom's sister Auntie as a child, it wasn't because she was smaller than you, it's because you loved her.

The use of O as an affectionate diminutive has recently become popular, as in kiddo and doggo.

Growing up, my mom called me Xiao Mei Mei.

Mei mei means little girl or little sister, and xiao also means little.

So my pet name was a double diminutive.

But diminutives show up in romantic relationships too.

Calling someone Baby or Sweetie, or even adding the E sound to the end of their name, like Andy or Katie, is a way to convey that you think they're a real, well, cutie.

- I have two nephews.

One is 11, one is one, and we'll call them Da Bao and Shao Bao.

Bao is treasure, Da is big, Shao is small, so it's basically Big Treasure and Small Treasure.

(relaxed music) (graphics popping) - Many terms of endearment represent wealth or value, like Princess, Treasure, or Jewel.

One of China's most popular pet names, first recorded more than 2,000 years ago, is Baobei, which translates literally to precious shell, referring to the cowrie shells used as coins during the Zhou Dynasty.

And in Danish, a common term of endearment is Skat, which means treasure, but can also translate to taxes.

Even the word dear originally meant costly or expensive, as in you'll pay dearly for this.

Are there any terms of endearment based on things like royalty or wealth?

- Yeah, so the firstborn son is usually called Raj or Raju, and that actually comes from what in Hindi is the king, so the highest one, the prince, the king, the most exalted person.

- And in the same way that Raj is used, Rani is used for a girl, so a Rani is a princess.

- Maybe like Princesa.

- My aunts will say Tesoro, which means treasure.

- Around the world, calling your beloved a name that evokes piles of money communicates that they are precious or valuable to you.

But why use these unusual terms of endearment at all?

Family dynamics researcher Carol Bruess found that terms of endearment are part of a larger linguistic phenomenon that couples engage in.

When we enter a relationship with someone, we form a culture of two by mirroring each other's vocabulary and speech patterns and coming up with nicknames to indicate alignment with each other.

- I wanna give everyone a nickname.

It's like it makes your connection with them like a little bit more personal.

- Researchers find that this style of idiosyncratic communication is especially important in newer relationships.

Couples who've been married for fewer than five years, and who haven't yet had kids, report using pet names the most.

Because what better way to communicate that you might be more than friends than calling someone by a name that not even their friends will use?

But even after the honeymoon is over, the insider lexicon we use in our relationship still serves an important purpose.

Couples that use pet names and baby talk in their relationships report higher marital satisfaction than those who cringe at the sound of Boo or Baby.

This may be because idiosyncratic language is a way of reinforcing one's social bond while setting it apart from our other friendships or family relationships.

Over time, we develop what Tiktokers might call marriage language, or what linguists call familects.

And social psychologists say these specific, and sometimes cringey, words and phrases we use inside relationships are part of building intimacy and trust.

These familects are made up of inside jokes, stories too embarrassing to repeat in public, and yes, terms of endearment.

So really, calling your partner Cutie Pie or Doodlebug is just a way of saying you're the only one for me.