What's the Best Age to Start Learning French or Spanish?

This question tends to come from two opposite directions, "is four too young?" and "is nine already too late?" and the research on this is more specific, and more reassuring, than the popular version of the story suggests.

Where the "window closes early" idea comes from, and why it is overstated

The idea of a critical period for language learning goes back to Eric Lenneberg's work in the 1960s, and for a long time the popular takeaway was that the window for learning a language well closes somewhere around early childhood or puberty. The most rigorous recent test of this came from Hartshorne, Tenenbaum, and Pinker (2018), who analysed data from roughly 669,000 English learners, the largest dataset ever used to study this question. Their finding was genuinely useful for parents: the ability to learn grammar to a high level is preserved almost all the way to around age 17, not early childhood as the popular myth suggests. After that point, ability does decline, but gradually, and a follow-up reanalysis of the same dataset found the decline is even more gradual and continuous than the original study suggested, rather than a hard cutoff at any single age.

In other words, the actual research window for strong language acquisition extends through the entire span most children would start lessons in, from preschool right through the primary and early secondary years. The idea that a child is already "too late" by age eight or nine is not supported by the data.

What differs by age is not whether learning works, but how it looks

Younger children (roughly 3 to 6) tend to absorb rhythm and sound with ease and often develop a more native-like accent, learning best through play, song, and repetition rather than explicit explanation. Progress can look slow on the surface while a real foundation is being laid underneath.

Primary age children (roughly 7 to 11) sit well within the window the Hartshorne et al. data describes as still highly capable of grammar acquisition, while also being old enough to notice patterns and ask questions about how the language works, often producing faster visible progress in speaking.

Older children and tweens (11+) are still comfortably inside that same window, and typically learn faster in early stages because they bring stronger literacy skills and pattern recognition from their first language, even if accent development takes a little more conscious work.

What matters more than the exact starting age

• Consistency. The retrieval and spacing research already covered in earlier posts applies here too, regular exposure over time outperforms an early start that fizzles out.

• A low-pressure environment. Krashen's affective filter concept, the idea that anxiety blocks acquisition regardless of input quality, applies at every age, not just early childhood.

• Quality of instruction. A skilled teacher working with a nine-year-old starting from nothing will generally get further than a generic programme with a four-year-old.

The best available large-scale research puts the effective window for learning a language to a high level much later than popular belief suggests, well into the teenage years. There is no age within the range most families are considering, from preschool to early secondary school, where the evidence says it is too late to start. At Passport 2 Learning, our French and Spanish classes are grouped by age precisely because a six-year-old and a ten-year-old both learn well, they just need different lessons to do it.

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.

• Slik, F., et al. (2022). Critical Period Claim Revisited: Reanalysis of Hartshorne, Tenenbaum, and Pinker (2018). Language Learning. (onlinelibrary.wiley.com/doi/10.1111/lang.12470)

• Krashen, S., Affective Filter Hypothesis, within Principles and Practice in Second Language Acquisition