What Is the Best Age to Learn a Second Language? Science Has an Answer

Is there really an ideal age to learn a second language? A large-scale study suggests that when it comes to achieving native-like mastery, starting young gives the brain a significant advantage.

Researchers analyzed grammar test results from nearly 670,000 people to investigate how our ability to learn a language changes with age. Their findings suggest that the brain remains remarkably efficient at language learning until around the age of 17 or 18 — but reaching full native-like grammatical proficiency usually requires starting much earlier.

According to the researchers, people who begin learning a second language by approximately age 10 can potentially achieve grammatical skills comparable to native speakers. After that point, language learning remains entirely possible, but the probability of reaching complete native-like mastery gradually decreases.

The findings support the idea of a critical or sensitive period for language acquisition. During childhood and adolescence, the brain's high level of plasticity may make it easier to absorb grammar patterns, pronunciation, and linguistic structures through exposure.

But adults shouldn't be discouraged. Older learners can still become highly proficient, especially with regular exposure, deliberate practice, conversation, and effective learning strategies. Adults also benefit from stronger analytical skills and existing knowledge that can help them understand grammar and organize their learning.

The best time to learn a language may be childhood — but the second-best time is now. Your brain remains capable of learning throughout life. Age changes how you learn, but it doesn't eliminate your ability to build vocabulary, understand grammar, and communicate fluently.

➡️ Related reading: Neuroplasticity Explained, The Complete Guide to Memory, and The Complete Guide to Spaced Repetition on Brain Geek to discover how practice, memory retrieval, and repeated exposure help the brain master complex skills.

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