Immersion, interactive, or rules-based learning? What's best?
Every few discussion threads, I keep seeing the topic of how best to learn a foreign language pop up. I think I should post some of my thoughts on this issue.
I think it's been proven so far that the best way to learn a language is through full immersion. However, even in full immersion programs, they explain grammar rules to the school children. My sister teaches French Immersion to grade school children and they stress grammar rules. I was taught French from grade 4 through high school and also through one year in university (I got placed in the advanced university course). For most of those years, I was learning French in as close to immersion as possible. (The program name was called "Extended French", "extended" because we also took other classes in French, such as history and geography.) They placed a lot of emphasis on grammar and understanding the structure used for the language (because they wanted the students to be literate as well as able to speak the language).
While it is true that during the earliest stages of life a person picks up their first language via experience, this doesn't mean that you can't pick up the grammar rules fairly early, especially once someone reaches school age.
The main reason why some "rule-based learners" would have problems with a language is that they simply have not internalized what they've learned yet by repeated exposure to the new material (this is part of why immersion works - repeat exposure). What I'm saying is that it's good for these types of learners to have some understanding of grammar and structure for the language so that they can stop asking "why?" all the time and then they can sit back and absorb the new material.
I wouldn't exactly call DuoLingo's method of teaching languages on here as "immersion" or even close to it, although it is interactive. In immersion, students don't focus on translation. They focus on understanding the language in context. The only part of DuoLingo that is like immersion is the exercises with pictures. In my opinion, DuoLingo should use more of those exercises, but they might be worried about being too close to Rosetta Stone's model. In comparison, Rosetta Stone is ideal if you wish to learn a language through context only.
However, the minute a language student starts to ask "Why?", I think it's good that the students gets accurate and detailed answers.
There are also other classes of language learners to consider: those with previous experience in learning a foreign language as well as those who have an academic or linguistic interest in a language. I think these classes of language learners will be more than ready for the "rules".
All this being said, I think that no language learning tool is valueless. If learning a language is mostly about exposure to it, then having more than one learning tool and different methods of learning is better than not having any at all.
I think even as children we learn through interaction and rules.
I remember my mother constantly correcting my English. She is why I don't say "I seen him" or "I done that" today. That was interactive.
And in third grade we learned the rules. Subject, predicate, noun, verb, and so on.
I personally do best with a combination. A bit of reading/talking/watching/listening, a bit of reading how the language works and what the rules are, and a ton of repetition and practice, preferably spaced repetition.
My experience with immersion has been that it does not always work well with grammar lessons. I went to an immersion school and took half my classes in Spanish (math was always in Spanish, and history and science switched between Spanish and English). We didn't learn about conjugation until second or third grade, and even then, never really took to grammar lessons. I think the helpfulness of rules depends on the context of the learning. For Spanish, I just get confused by grammar lectures and do better when I ignore them all and just say what sounds right, but for German, I wish there were more explanations. I think that grammar explanations are great for learning a language through the normal school model of memorizing vocabulary and translating sentences, but can get in the way of an instinct for the language from immersion.