That dreaded 8 am Spanish class. Nothing is worse for me than waking up early to struggle to memorize tedious endings to verbs and vocabulary words. Times like these I am extremely jealous of anyone who lived in a multi-language home growing up. Key words in there were growing up. Now why does it seem that kids raised around two languages seem to pick them both up with extreme ease, no memorizing and studying? It always seemed to be common sense that children picked up languages, like most other concepts, more quickly than adults or even teenagers, but why? I bet you do not really remember learning English. It almost seemed as natural as learning to walk. You did not have to overthink grammar rules too much (except for like first grade), but it’s nothing compared to trying to learn Spanish. The answer to the question probably has something to do with brain development.
In 1967, Lenneberg formed a hypothesis that our brain’s only had a critical frame where language was easiest to acquire. This still seems to remain the popular belief and observation today, as I stated in the opening. People generally assume that children process and retain a second language much easier than adults can. This is definitely a hard thing to study, especially keeping all the third variables that would affect the null hypothesis that children learn second languages faster, including how often the language is exposed to them, and how focused the adults are to learning it considered they face many more distractions/responsibilities compared to a child.
Going back to Lenneberg, most studies that agree with the argument that youth is better for language learning agree that there are neuromuscular mechanisms that work better early on in youth to process information and make connections. One scientist used brain scans to try to prove the point that the language capacity decreases with age. Monika Schmid, a professor at the University of Essex, used an interesting experiment to measure the brains by scanning them. She gave sentences with grammar mistakes to native speakers and people who learned it later in life as a second language. She found the people who learned later were less quickly to recognize small errors unlike the natives. The age ranges in the observational study were not specified which led to the conclusion that there was no particular age that was best to learn.
Another small randomized observational study was conducted by Petitto, PhD. This tiny study concluded the same thing as the first mentioned. The kids who picked up the second earlier were better at it. This study by Petitto also however noted that the kids learned better in their community through conversation, rather than in the classroom. Both of these observational studies agreed that the younger the better.
A contrary experimental trial was performed right here at Penn State. This trial provided different results than the previous two mentioned. The researchers conducted a brain scan on 39 English speakers. The speakers then went through lessons in mandarin and after 6 weeks the brains were scanned again. The results showed brains with more functional changes and greater activity than they assumed from a 6-week course. This was definitely evidence against the argument: aging results in more difficulty learning the language. The researchers suggest the brain was more plastic than they thought which means it has a greater ability to learn new things and form more of those connections associated with learning a new language.
What do the results of these small observational and experimental studies say? I keep stressing small because every one of these trials was indeed very small, with the most being only over 100 people. The p-values were definitely high which could have resulted in two false negatives and a false positive. However, these do suggest that scientists are heading in the right direction while studying the brain If they can even pick up tiny functionalities like this with scans. The answer is definitely looming, and with larger trials the p-values can conclude these findings less likely due to chance.