Evidence-based answer · Last updated · How it’s made
The idea that learning a language gives you a general "smarter" boost in unrelated mental skills (the so-called "bilingual advantage") is heavily contested — large, high-quality reviews and meta-analyses find little to no reliable evidence for it once publication bias and study quality are accounted for. Some individual studies, especially in older adults, do report gains in specific attention or memory tasks, but these tend to be narrow, inconsistent across labs, and comparable to what you'd get from any mentally engaging activity (like brain-training apps), not a special superpower unique to language learning.
Answered for language learning in general. No specific language was set for this question, so the findings are drawn from general second-language research rather than one language’s literature.
Multiple large meta-analyses find that once you correct for publication bias, the overall effect of bilingualism on general executive-function tests (unrelated skills like attention, memory, or self-control) is statistically indistinguishable from zero.2,3,5,7,9
In plain terms
This isn't unique to language learning: a broad second-order analysis of cognitive-training research (brain-training games, working-memory drills, chess, music, exergames) found the same pattern — training reliably improves the trained task itself but shows little to no spillover into unrelated abilities.2,3,9
One theoretical account argues that being bilingual doesn't 'transfer' skill to other domains but instead makes the brain's attention system more efficient overall, so bilinguals may need less mental effort on tasks that already demand a lot of attention — without necessarily outperforming others on easier tasks.4
In plain terms
A study testing over 11,000 people online on 12 different unrelated cognitive tasks found bilinguals only outperformed monolinguals on one task (monolinguals actually did better on four), and even that tiny advantage vanished once groups were matched for other differences like education or socioeconomic status.7
When bilinguals and musicians were compared head-to-head in the same study, musicians showed a reliable working-memory boost but bilinguals did not — suggesting any 'smarter from a hobby' effect may depend heavily on what the specific activity trains, and language learning isn't clearly a stand-out.1
In older adults, several intervention studies (using apps like Duolingo, or in-person courses) found real but narrow improvements — in things like Stroop-task performance (a measure of ignoring distracting information) or response inhibition — that were often comparable to what dedicated brain-training apps produce, not extra gains unique to language learning.6,11,14,15,16
In plain terms
One randomized trial found foreign language learning didn't generally improve executive function, but people who started with lower baseline cognitive ability improved more than those who started with higher ability — suggesting any benefit may show up mainly in people who have more room to improve.14
Several reviewers describe the field as being at a scientific 'impasse,' with some individual studies (including recent replications and studies in children) still reporting bilingual advantages in specific tasks like task-switching, even while larger reviews report null results overall — so the picture is mixed rather than settled in either direction.8,10,12,13
Now pick something to do it with
Each of these opens an overview of the apps, courses and immersion material worth a look for that — filtered to exactly what the advice above points you at:
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