On the terrace of a brasserie on Rue Cler, a chic Parisian market street, I’m chatting over a tongue-lubricating glass of Sancerre with Sébastien de Lavalette, 33, a French travel company head and my language exchange partner.

Sébastien compliments my French accent, or at least I think he does: “You don’t have that mouth-full-of-bread accent that many British people have”, as I order in my middle-of-the-road restaurant French. Sébastien, who was raised in Paris but whose family hails from Périgord, reminisces about his teenage foreign language exchanges in Spain.

“At 17 I was already 190cm,” he recalls, switching to English. “So I was allocated to a family on the outskirts of Granada as I was considered safe to be on my own. All I did that week was drink sangria, smoke cigarettes in a cantina and learn a bunch of Spanish swear words!”

I’m staying with Sébastien for a couple of days in his Parisian atelier in the 7th arrondissement, shadowing him in his day-to-day life in an attempt to improve my rusty A-level French through forced immersion. My language skills have waned to transactional brasserie and Métro station French, so this year I decided, having heard about the growing trend for adult language exchanges, that it was time to take the plunge.

This isn’t my first foray as a language exchange student. In 1993, my Birmingham comprehensive matched me for a French exchange with Sylvain, who was male, two years younger than me and a superfan of the 70s British crooner Des O’Connor (which he pronounced “Dess-conner-r-r”). Then came a swap with Aurelie in Lyon, Birmingham’s twin city. Her sister made me transcribe the English lyrics from the Dirty Dancing soundtrack and we ate bright pink crevettes with a strong aioli.

Whether it’s down to fond recollections of such youthful experiences or the rise of online and app-based peer-to-peer language exchange services that facilitate such swaps, adult exchanges are gaining in popularity.

Online portals offering to match would-be swappers include Lingoo (which allows users to arrange in-country homestays with language teachers from £33 a year); Tandem (“social media for language learners”); Kuno, a mutual learning-exchange app that allows members to offer language lessons to other learners and arrange informal exchanges (which is where I’d come across Sébastien); and the subreddit r/language_exchange, where users post their offered and sought languages for online and real life swaps. Stays can be for individuals or families, reciprocal or one-way, and free or sometimes paid for, especially if the host is a qualified language teacher who can offer lessons as part of a hosted experience.

The appeal of a language exchange as a midlife adult, for me at least, is partly a newfound chutzpah. Whereas in my 20s I would mumble requests for breakfast pains au chocolat, self-consciously stumbling over tenses and tu and vous, in my 40s I care less about what any French interlocutor thinks of my mastery of their native tongue.

As Sébastien is a tour guide rather than a French teacher, we decided that, on this unremunerated peer swap, I would shadow him in his daily life about Paris – as teenage swappers typically do – and we would toggle between French and English as we strolled alongside the Seine, stopped off for lunch and shopped in the local marchand de fruits et légumes and supermarché. It’s as common, however, for adult swappers to stay with a family where someone has formal language teaching skills, and combine cultural and family immersion with paid lessons.

Mark Thompson, 62 and from Bath, worked in Zaragoza in northern Spain for a year in the 1990s before pursuing a career in education. After taking up online Spanish-language classes during Covid lockdowns he signed up for Lingoo to seek out Spanish-speaking e-penpals and then decided to go on an exchange. A stay with the Crespos family, who live on a smallholding on the outskirts of Peñaflor de Gállego, north of Zaragoza, was great for his language skills. “The family are into de-growth – decrecimiento they call it in Spanish – and they live a very low-impact life. I even accompanied them to a permaculture gathering,” he says. “It was utterly delightful – real sink or swim stuff on the language front!”

John Grummitt, 52, a former overseas TEFL teacher and singer-songwriter based in Saltburn-by-the-Sea in North Yorkshire, hosts adult language learners from mainland Europe through Lingoo and the homestay hosting site InTuition Languages. Fish and chips in Whitby and a performance by John’s sea shanty group, Saltburn Smugglers, are often on the agenda, as well as professional English lessons, offering immersion in local life. “It’s nice that our kids, who are aged four and seven, get to chat to our guests about their home countries too,” says Grummitt. He plans to take his two young children on an all-family language exchange when they are a little older too. “I think kids over the age of 10 get the most from an immersive overseas experience,” he says.

Both agree that adult homestay guests have a different approach to the experience than teenage exchangers. “I did more in three days in Zaragoza as a 62-year-old than I did when I lived there for a year when I was younger,” Thompson laughs.

At Sébastien’s home, a grand high-ceilinged family apartment, which is littered with gaming and millennial tech (as well as pictures of his American girlfriend, who is busy learning French with a language partner on Kuno), Sébastien agrees that times have changed. For one, he doubts his misspent week of teenage inebriation in Granada would be permitted in the new age of safeguarding. In his view, however, the fact that adults are embracing lifelong language learning is “a fabulous thing”.

As, reliably, is a sojourn in Paris. As we strolled the streets, my chats with Sébastien ranged from young Parisians’ take on the plans to reopen the Seine for wild swimmers (“Parisian men don’t like to parade about in shorts, let alone swimming trunks”) to the disgruntlement of the elderly pétanque players being ejected from their central Paris pitches, and my French language acquisition came on a treat.

What would Sébastien like to do when he visits us in leafy, lefty Lewes soon? “Immersion in British humour is the thing French people really like,” he says. “Oh, and the pubs. Not the British food, though, I’m sorry: not even fish and chips!” And with that gesture of entente cordiale I’m bound for Gare du Nord and the Eurostar with some new linguistic confidence.

Train tickets to Paris were provided by Eurostar and cost from £39 each way; eurostar.com

• This article was amended on 16 October 2024. The Crespos family live on the outskirts of Peñaflor de Gállego, north of Zaragoza, not on the outskirts of Peñaflor, east of Seville, as an earlier version said.