Is it too late to learn a language? The research
Is it too late to learn a language? No. The largest study of the question, which tested 669,498 people, found that the ability to learn grammar stays strong until about 17 or 18 and then declines slowly, and that people who want to sound exactly like a native speaker do best to start by about 10. Neither finding says an adult cannot learn a language well. Adults start out learning faster than children, and almost nobody's real goal is to be mistaken for a native. Below is what the research found, what it did not find, and what it means for someone starting at 30, 50 or 70.
The study: two thirds of a million people
In 2018 Joshua Hartshorne, Joshua Tenenbaum and Steven Pinker published A critical period for second language acquisition: Evidence from 2/3 million English speakers in the journal Cognition. Their problem was one that had held the field back for decades: small studies. To separate the effect of the age you start from the effect of how long you have been learning, you need a huge number of learners who started at every age.
They got them with an online grammar quiz, built to be fun enough to share. It asked people to judge English sentences, guessed their native language and dialect from the answers, and then asked about their language background. It was shared more than 300,000 times on Facebook. In the end 669,498 native and non-native speakers of English took part.
What it found
Grammar-learning ability is preserved almost to adulthood. The model that fitted the data best had learning ability staying high until 17.4 years old, and then declining steadily. The authors note that this is much later than most earlier studies had suggested.
To reach a native speaker's level, start by about 10 to 12. People who began then could still end up indistinguishable from native speakers on the test. Those who began later did not, and the reason is time: in the authors' words, they "literally run out of time before the sharp drop in learning rate at around 17–18 years of age". Mastering a language's grammar to a native standard takes so long that you need a head start.
Even native speakers keep learning for a long time. The data suggested native speakers do not reach their final level until about 30, though most of the learning happens in the first 10 to 20 years.
What it did not find
The study is often summarised as "it's too late after 17". It does not say that.
- It measured grammar only. The quiz tested whether people judged English sentences as a native speaker would. It did not measure vocabulary, pronunciation, conversation or reading. A learner can be fluent, articulate and widely read while still making the odd grammatical choice a native would not.
- It measured native-like mastery. The finding concerns the very top: being statistically indistinguishable from someone raised in the language. Everything short of that, including comfortable fluency, remains open at any age.
- It found a slow decline, not a wall. Learning ability declines after 17 or 18; it does not stop.
Adults learn faster at first
Hartshorne and his colleagues point out a finding that runs the other way. Studies that look at the first weeks or months of learning, in the lab or in immersion programmes, "show that adults perform better, not worse, than children", perhaps because adults use conscious strategies and can draw on what they know about their first language. Children's advantage only shows up over many years.
So an adult who starts today will make faster early progress than a child starting alongside them. The child will probably end up with the more native-like grammar, but only after a decade or more.
What this means if you are starting now
Set the goal you actually have. Most people learning a language want to talk, read, travel, work or connect with family in it. That is fluency, and fluency does not require passing as a native. The research says nothing to discourage it at any age.
Use the adult advantages. Adults learn faster early on, can study deliberately, and can use what they already know. A related language shares a great deal of vocabulary with English: see what language is closest to English and the easiest languages to learn.
Learn the most common words first. A few thousand words cover most of what is said in any language, so frequency order gets an adult to useful conversation fastest: see how many words you need to speak a language.
Keep going. The study's native speakers were still improving at 30. Learning a language is a long project at every age, and the people who succeed are mostly the ones who keep at it.
How long will it take?
That depends on the language and on how much time you can give it. The estimates for each language Verbavia teaches, from the US Foreign Service Institute and others, are set out one by one:
- How long to learn Spanish
- How long to learn French
- How long to learn Italian
- How long to learn Portuguese
- How long to learn German
- How long to learn Mandarin
- How long to learn Esperanto
- How long to learn Māori
Verbavia (our own course) is built for adults learning in short daily sessions: one lesson a day, the most common words first, free on the web.
Sources
- Hartshorne, J. K., Tenenbaum, J. B. & Pinker, S. (2018). A critical period for second language acquisition: Evidence from 2/3 million English speakers. Cognition 177: 263–277. Full text (PMC). The figures and quotations above are from the paper: 669,498 participants; learning ability preserved to 17.4 years; native-level attainment requiring a start by 10–12; native speakers reaching asymptote around 30; adults outperforming children in the initial stages, citing Snow & Hoefnagel-Höhle (1978), Krashen, Long & Scarcella (1979) and Huang (2015).