“French resistance” took on an entirely new meaning as my brain repelled every strategy I employed. Yet my failure was in fact quite unremarkable. Advertising claims notwithstanding, few adults who tackle a foreign language achieve anything resembling proficiency. In the end, though, it turns out that spending a year not learning French may have been the best thing I could’ve done for my 57-year-old brain.

In the last few years, unable to hold a list of just four grocery items in my head, I’d begun to fret a bit over my literal state of mind. So to reassure myself that nothing was amiss, just before tackling French I took a cognitive assessment called CNS Vital Signs, recommended by a psychologist friend. The results were anything but reassuring: I scored below average for my age group in nearly all of the categories, notably landing in the bottom 10th percentile on the composite memory test and in the lowest 5 percent on the visual memory test.

This, obviously, did not bode well for my nascent language project, but I forged ahead. To be sure, learning a foreign language is a daunting task for any adult. How can something that a toddler accomplishes before learning to tie his shoes be so difficult for grown-ups?

Psycholinguists are divided on the answer, but they agree on several points. For starters, a 2-year-old’s brain has a substantial neurological advantage, with 50 percent more synapses — the connections between neurons — than an adult brain, way more than it needs. This excess, which is an insurance policy against early trauma, is also crucial to childhood language acquisition, as is the plasticity, or adaptability, of the young brain.

Once the “critical period” — the roughly six years of life during which the brain is wired for learning language — is over, the ability to acquire a first language is lost, as your brain frees up room for the other skills you’ll need as you mature, such as the ability to kill a wild boar, or learn math, or operate your iPad.

Another advantage a toddler holds is his very lack of experience. After speaking our native language for decades, we adults can’t help but hear the second language through the filter of the first. And this filter doesn’t take decades to develop. Researchers have found that newborn Japanese babies can distinguish between the English “L” and “R” sounds, but if not exposed to Western languages, they begin to lose that ability — not by the age of 6 or even 3 — but by eight months.

Adult language learners are, to borrow a phrase used by some psycholinguists, too smart for our own good. We process too much data at once, try to get everything right from the get-go and are self-conscious about our efforts. But toddlers instinctively grasp what’s important and are quite content to say, “Tommy hitted me,” as long as Tommy gets what’s coming to him.

All this means that we adults have to work our brains hard to learn a second language. But that may be all the more reason to try, for my failed French quest yielded an unexpected benefit. After a year of struggling with the language, I retook the cognitive assessment, and the results shocked me. My scores had skyrocketed, placing me above average in seven of 10 categories, and average in the other three. My verbal memory score leapt from the bottom half to the 88th — the 88th! — percentile and my visual memory test shot from the bottom 5th percentile to the 50th. Studying a language had been like drinking from a mental fountain of youth.

What might explain such an improvement?

Last year researchers at the Chinese University of Hong Kong and Northwestern University in Illinois hypothesized that language study should prove beneficial for older adults, noting that the cognitive tasks involved — including working memory, inductive reasoning, sound discrimination and task switching — map closely to the areas of the brain that are most associated with declines due to aging. In other words, the things that make second-language acquisition so maddening for grown-ups are the very things that may make the effort so beneficial.

The quest for a mental fountain of youth, pursued by baby boomers who fear that their bodies will outlive their brains, and who have deeper pockets than Juan Ponce de León, has created a billion-dollar industry. There is some evidence that brain exercise programs like Lumosity and Nintendo’s Brain Age can be beneficial, but if my admittedly unscientific experience is any indication, you might be better off studying a language instead. Not only is that a far more useful and enjoyable activity than an abstract brain game, but as a reward for your efforts, you can treat yourself to a trip abroad. Which is why I plan to spend the next year not learning Italian. Ciao!