“How’s your French coming along?” The familiar voice, accompanied by a light tap on my shoulder, surprised me.

I turned and saw a former girlfriend, who was born in the Ivory Coast and raised in Paris.

“Comme ci comme ça,” I responded as I accustomed myself to her unexpected presence.

In reality, I’d barely spoken a word of French since our amicable breakup a decade earlier. After our fleeting chance encounter at the Museum of Modern Art, I wondered: If our relationship had endured would I have continued taking the French classes I had started? Or would she have succumbed to the gravitational pull of Lingua Britannica.

That meeting made me wonder about multilingual couples and whether they speak their partner’s native language. What about couples who had more than two languages between them? If the couple was fluent in each other’s native language, what was their language of love? Did one language prevail over the other in everyday use, and if so, why?

According to data from the U.S. Census Bureau, the number of households speaking a language other than English increased to 28.7 million in 2021 from 25 million in 2015. During that period, the percentage of households speaking a language other than English rose to 22.5 percent from 21.2 percent.

Michael Kaye, the head of global communications at OkCupid, said people who speak two to three languages got 11 percent more matches and 22 percent more likes on the dating app over the last 90 days than those who only speak one language. This was based on an in-app question that has been posed on the OkCupid app since 2009.

Mr. Kaye said that when it comes to preferences on the app, 92 percent of people worldwide are fine being matched with people who don’t speak English.

Ingrid Piller, a professor of applied linguistics at Macquarie University in Sydney, Australia, said this receptivity is likely related to greater mobility through temporary and permanent immigration as a result of educational and employment opportunities.

“Multilingual couples may face unique challenges,” wrote Nai Chieh Tien, in her 2013 dissertation about multilingual couples and language differences. “Individuals who are bilingual or multilingual learn the second or third language at different times in their lives, and develop a variety of attachments and relationships when using different languages.”

Jean-Marc Dewaele, a professor in applied linguistics and multilingualism at Birkbeck, University of London, said during an interview on the podcast Raising Multilinguals LIVE, “You may prefer to use a specific language in a specific domain. For example, English is very much my academic language, maybe also my social language, these days. But it’s not the language I would read poetry. And because French is my language of poetry, it’s closer to my heart.”

The Times asked several couples to share how they navigate the heart-shaped expectations of their multilingual relationships. Here are the accounts of five couples.

Fiore di Fabrizio and Jennifer Miller-Wolf

Penne, Italy

“My Italian was at the complete beginner’s level, but still exceeded his nonexistent English,” said Jennifer Miller-Wolf, 61. She met her husband, Fiore di Fabrizio, 66, in early 2020 just before the pandemic lockdown. They were members of the Penne-Abruzzo chapter of Club Alpino Italiano, a hiking and mountaineering organization.

Ms. Miller-Wolf, who had recently relocated to Italy, said she and Mr. di Fabrizio, an independent solar energy contractor, “bumbled along in my broken, Italian, and some version of hand sign language, at which the Italians are quite talented.”

“I do not find Italian as romantic a language as most of my friends,” said Ms. Miller-Wolf, a retired teacher of French and German from Saratoga Springs, N.Y. “Quite frequently, it sounds to me as if they are having a disagreement, even if they are not.”

In the end, she deferred to her husband’s language because, for one thing, she was living in Italy. She also picks up languages more quickly than he does, she said, “although a few English endearments — ‘sweetie,’ ‘honey,’ and ‘I love you’ — are finally making their way in every now and then.” On such occasions, she said, she praises him with, “Honey, you’re learning,” first in English, then in Italian to make sure he understood.

“There’s something about hearing ‘I love you’ in your own native tongue, it somehow touches you deeper,” she said.

Ms. Miller-Wolf found that her husband responds differently when she speaks to him in Italian.

“If I say something like, ‘Oh, give me a hug,’ it takes him a minute to get it in English,” Ms. Miller-Wolf said. “He kind of doesn’t react because he needs to register it first. If I say to him, ‘teso’, which is short for ‘tesoro,’ treasure, he’ll immediately turn to me. His face will light up and he’ll come right over and give me a kiss.”

Michael Lemay and Jorge D. Aguilar

Washington, D.C.

“My mother is from Central America,” said Jorge D. Aguilar, 38, an attorney for the Treasury Department in Washington. “I grew up in Miami and moved around the East Coast speaking Spanish and English at home. I learned French in high school.”

Michael Lemay, 46, a statistician with the U.S. Census Bureau in Washington, grew up in rural Quebec where he spoke only French at home, he said. He became fluent in English while attending undergraduate and graduate school in the United States.

The couple met in March 2018 at a bar in Washington.

“We had one of those great talks during which you sense you have known this person for so long,” Mr. Aguilar said.

Their first conversations were in English, but as their relationship evolved, French became increasingly important in communicating affection and romance.

“I think one major reason we started moving to French was when, several months into our relationship, we acknowledged we loved each other,” Mr. Aguilar said. “French was the language we chose to use in expressing that mutual, meaningful sentiment.”

Mr. Aguilar added, “English is the language of everyday life — what I use when giving strangers directions or booking dinner reservations. But love is profound and transcends the commonplace.”

Robert Rohrschneider and Rebecca Rovit

Lawrence, Kan.

Rebecca Rovit and Robert Rohrschneider, both 63, met on a train in Germany in 1982. They were returning to the University of Freiburg, where they were both students, although they didn’t know each other.

They chatted amicably in German on the train, then went their separate ways. Two or so weeks later at the university, they chanced into each other on campus, and she said in German, “Oh, you’re the guy from the train! How are you?” (“Wie geht es Dir?”)

“That was the beginning of our relationship and life together,” she said.

“We spoke German exclusively, with occasional English words,” said Dr. Rovit, an associate professor of theater at the University of Kansas, in Lawrence, where her husband is a distinguished professor of political science.

It wasn’t until the fall of 1983 — over a year after they first met — that the couple began speaking English to each other when Dr. Rohrschneider came to the United States for a graduate fellowship at Michigan State University.

“The gradual switch came about because we were both living in a predominately English-speaking environment,” Dr. Rovit said. “And he was using English every day. In Europe, we tend to speak more German with one another.”

“We use both English and German to express our love and affection,” Dr. Rovit said. “We mix the languages. It feels more natural and true to use our native tongues. The words of our birth languages are heartfelt, and their sounds, familiar and comforting.”

The couple married in May 1990 in Lexington, Ky.

“When we got married,” Dr. Rovit said, “we each said our wedding vows aloud in our native language: I in English and he, in German. I felt that such important words before friends and family had to be expressed in the language we knew best. That way we could be sure we meant what we said!”

Eveline de Smalen and Douglas Bell

Groningen, the Netherlands

Eveline de Smalen, 30, is a curator at Wadden Sea World Heritage Center in Lauwersoog, the Netherlands; Douglas Bell, 38, is a history teacher at Rotterdam International Secondary School.

The couple met in October 2015 at the Ludwig Maximilian University of Munich, where Dr. Bell, who is American, and Dr. de Smalen, who is Dutch, were doctoral students.

“We started spending more and more time together,” said Dr. Bell, noting their mutual love of museums, hiking, traveling, cooking and baking.

During a trip to Italy together in the spring of 2016, their relationship blossomed and became romantic, but as of that August, it also became long-distance. Dr. Bell’s fellowship ended and he had to return to the United States. They remained in contact with daily texts and video chats. They also visited each other every few months until he relocated to the Netherlands roughly five years later.

“Until I moved to the Netherlands in April 2021, we spoke almost exclusively in English to each other,” Dr. Bell said. “Starting in 2017, we started using Dutch phrases of affection. Since arriving in the Netherlands, I have developed a high proficiency in the Dutch language. Today, we speak Dutch to each other for basic conversation, but we speak English for more complex topics.”

“We most often express our love and affection in Dutch,” he said. “We frequently use: ‘Ik houd van jou’” (which means I love you in Dutch). “We most often address each other with the word ‘liefje’ or ‘lief,’ which means ‘my love’ or ‘dear’ in Dutch. We also use a version we made up: ‘lieffie lief’ that is not used in Dutch, that we know of.”

Dr. Bell said that speaking Dutch to his wife is how he shows affection, while also acknowledging that her language is important to him.

“We expressed and express our affection in Dutch because it was a way for me to engage in my wife’s language and demonstrate my love and affection for her in her own language.” Dr. Bell said. “She very much liked and likes that we express our love in Dutch since English is our default language.”

Amanda Lopez and Rob Ciesielski

Manila and Washington, D.C.

Languages were central in the lives of Amanda Lopez, 37, and Rob Ciesielski, 42, before they met. In August 2021, both were subscribed to Duolingo, a language-learning app and website. Ms. Lopez, who lives in Manila, was learning Mandarin; Mr. Ciesielski, who lives in Washington, was learning Spanish. Her Duolingo profile information included a photo. He later said he reached out to her in part because of her “cuteness.”

He couldn’t message her using Duolingo, so he said he reached out to her by clicking her “congratulate” button for each consecutive language lesson she completed. She did the same with him. This went on for weeks.

“I hoped this beautiful Amanda Lopez (who I assumed lived in Orlando or Queens, not the Philippines!) would find me on Facebook with my unusual surname, which she did,” Mr. Ciesielski said.

With the Covid pandemic prevalent around the globe at the time and being half a world away from each other, their relationship developed via phone calls and video chats.

“We mostly use English but the words that express exactly what we mean at any given time simply do not exist, and so we do our best to approximate,” said Ms. Lopez, who writes brand and communications content for an accounting firm in Manila.

“Because we were worlds apart, we used the language of creativity to strengthen our connection,” said Mr. Ciesielski, who visited Manila in July 2022 and met Ms. Lopez in person for the first time. “We would create new words together, often blending Tagalog and English to inspire brand-new neologisms.”

“Amanda taught me that ‘tampo’ is a Tagalog word that describes the state of being emotionally bruised and making it known to the offending party,” said Mr. Ciesielski, an event florist manager in Washington. “In other words, it’s being especially sensitive and demonstratively upset. Since I claim to be some sort of poet, we came up with ‘tampoet’ to indicate a sad poet.”

“The Tagalog word ‘kilig’ refers to the exhilaration brought about by a romantic experience and does not exist in English,” Ms Lopez said. “The word ‘giggle,’ which means ‘to laugh lightly, nervously, or in a silly way,’ does not have a direct counterpart in Tagalog. Rob actually created the word ‘kiliggle’ — which is the giggle that accompanies feelings of ‘kilig.’”

Mr. Ciesielski, who married Ms. Lopez on Jan. 18 in Manila, said, “She’s enlightened me on concepts like ‘lambing,’ which means to sweetly caress and hug.”

Ms. Lopez, who said she speaks, writes, and thinks in both Tagalog and English, refers to Mr. Mr. Ciesielski as “mahal ko,” which is Tagalog for “my love,” or to be more specific, “love of mine.”

“‘Mahal ko’ to me,” Ms. Lopez said, “just feels a tad more ‘kilig!’”