Children Pick Up New Languages Most Easily Before Age Seven
After that, the ability to pick up another language declines steadily, then falls further after puberty.
TED · The linguistic genius of babies | Patricia KuhlChildren pick up new languages most easily before they turn seven. After that, the ability declines steadily, and it falls further after puberty.
That is the shape of the critical period for language. On a chart of ability to pick up another language against age, young children sit at the top. At about seven, the line starts to go down.
By adulthood, that ability has fallen further. Adults hearing a language they never learned rarely pick up new sounds the way babies do.
The takeaway is that timing matters a great deal for picking up a second language.
Questions people ask
Does that mean adults cannot learn a second language at all?
No. Adults can become fluent with study and practice, but they rarely reach native-like pronunciation and effortless grammar. The decline is in the brain's automatic pickup of sounds and patterns, not in the ability to learn through effort.
Why age seven?
Seven is an average turning point, not a birthday alarm. Brain imaging and language tests suggest the circuits for hearing and reproducing speech sounds gradually commit to the sounds heard most in childhood. That commitment makes the native language efficient, but makes new sounds harder to hear and copy.
What happens at puberty?
Puberty has long been used as a marker for the end of the most flexible period for language. Hormonal and brain maturation changes reduce plasticity, the brain's ability to reorganize itself. Researchers still debate how sharp that cutoff is, and motivation, instruction, and exposure matter a great deal afterward.