I studied French at school for five years, hated it, and learnt very little. Then at age 22 I started evening classes in French and 5 years later I moved to Montreal for 2 years, sharing a flat, and working, with francophones. I developed good comprehension of standard French spoken a bit slower than normal, but I could not speak, my grammar was awful, and my vocabulary limited. I never could understand joual.
Fast forward 30 years, and after 15 months of a refresher course then huge amounts of comprehensible input (podcasts), I can understand most native French podcasts with ease, and I can communicate. My spoken French is not advanced, but grammatically (mostly) correct, I can use the commonly used past, future and present tenses and the subjunctive. And I have a decent vocabulary. In short, I have learnt far more from comprehensible input at home, then I did in Montreal.
In my case, immersion did not work. Children and adults are very different:
- Children learn through play, using a simplified language, with no real consequences from making errors.
- They are more relaxed, with no time constraints.
- They will often repeat things, as part of play.
- They pick up the grammar naturally, as well as a perfect accent. They seem to be more observant, or adept at seeing patterns.
- There are biochemical differences. At least two groups of chemicals are present in greater quantities in kids brains, and those chemicals facilitate learning. Children learn much faster than adults. I saw this when learning ice hockey. The kids advanced 5 times faster than me.
Adults engage in mostly transactional relationships, they are often stressed, they have time constraints, they use a much larger vocabulary, and they are usually impatient. I was unable to pick up the grammar naturally. In fact I have to study grammar first, then when I hear it, I learn it. For me grammar study is part of the comprehensible input process. One colleague got on my nerves by correcting my French. C’est pas grave was wrong, I was to say Ce n’est pas grave. C’est pas la peine was wrong, I was to say Ça ne vaut pas la peine, and yet all the French speakers used the ‘incorrect’ forms. I was also told off for my Quebec accent, I was to speak like the French from France. Unfortunately some people think they are great language teachers, as he did because he was fluent in English and French, when in reality they are completely incompetent and have no understanding of language acquisition. Eventually I spoke only English, as the corrections were driving me mad, confusing me, and destroying confidence.
In my opinion adult learners are totally different from children, their brains are biochemically different, their circumstances are different, and they have to use different methods. As adults we can master a foreign language to a high level, but we have to use our own approach.
As to the suggestion that we can use AI to create language partners, that has merit, in my view. They could create a supportive learning environment akin to that experienced by children. We live in fantastic times, as far as second language acquisition goes, and they improve each year.