I'll add my vote and 2 cents for language immersion. Learning a second language seems to be a lot like learning to read in a first language. As a child I thought I was reading when I leafed through a book and recited all the words correctly, with page turns at the right places. Part of me doubted it could be that easy. When I actually learned to read I realized I had only been reciting from memory.
The same happened with learning a second language. What I thought was speaking was really translating - and it was way too slow for normal conversation, so part of me again recognized something was wrong. When I actually learned to think in another language (and started dreaming in that language), I recognized the difference for the first time. That only happened during an immersion program. (It helped that it was in another country, where the opportunities to speak English were limited.)

At one time, 40 years ago, I had a merely okay command of German, seemed able to think in the little German I had command of, and generally was able to enjoy the months I spent in Germany because of that.

I certainly feel cheated that I don't really know another language, and I'm jealous of those I've meet in Europe who seem quite comfortable, and quite capable in 3 or 4 European languages and brush it off as no big deal. And not just European countries.

A couple is years ago, we spent two weeks in Egypt. In the more touristy areas, every shop keeper and clerk were able to speak in the native languages of every tourist who came in, be they spanish, english, german, italian, or french speaking. This was even true of street vendors selling bric-a-bracs, or fruit on various street corners. Their command of these other languages was likely situational and perhaps narrow in scope, but they were good at what they did, very good.

While I think it embarrassing that most Americans cannot speak another language, and think immersion is the best way to learn a new language, I don't know how this affects education generally.

There is a vast difference between conversational knowledge and academic knowledge in a language. We teach English to native English speakers because there is not much you can learn or understand if your vocabulary and sentence structure knowledge remains at the level of conversational English.

So, when we speak of ESL, or learning Spanish, or Chinese, or German, or French using immersion or other pedagogical technique in our schools, what knowledge of a language are we expecting or requiring students to acquire, and what level of language knowledge are we expecting the teachers to have?

When we demand that all students be reading at grade level by 3rd grade (I'm presuming in English), what level of command of English are we expecting, and is that feasible for those coming in with no English or poor conversational English knowledge?