Why "Dual Immersion" makes sense and works, if...

...you have the right student body ratio. In the earlier post about Ratios, I brought up the issue of "one-way" vs. "two-way." Why would it be called "two-way"?

"One way" is for speakers of a language that they all know (in this case it is English) to go all in "one way," that is, learning in the same direction to onboard to the language they do not know.

In "two way," there is a group of students going towards one of the languages, and another group of students going towards the other language. In the case of Dual Language Immersion for Mandarin and English, that would be one group of kids going toward Mandarin and another group going toward English. These two groups of kids then complement and help each other along the way. 

But what happens in a DLI program when most of the kids are going only "one way," that is, towards Mandarin, but not enough kids are going the other way towards English?

That is where things don't work. There are not enough resources to make the language that most of the kids don't know into a "living language." Without the "living" quality of the language, then it is reduced to dry, staid language that sits in a vacuum. This makes learning much harder, slower, and far less effective.

"The kids learn from each other," is a statement that I read and heard from "the experts" again and again.

But if there are no kids to learn Mandarin from, or if there are far too few of them, then the kids resort to the majority language. They resort to English and learning Mandarin is not optimized.

Parents then say, "Well, my kid is supposed to learn from the teacher who is supposed to be speaking Mandarin 100% of the time." Y'know, this is how a lot of ABC's learned Mandarin. By listening to our parents, and eventually, we spoke all English back to them, until they then started speaking English back to us, too. And then most ABC's didn't learn their Mandarin very well and barely have many skills to speak of today. 

Besides, there have been many formal studies done now that have shown that Two-Way or the DLI method is more effective than One-Way. But if you don't have all the variables in place for DLI to exist in the first place, then you cannot have a more effective anything in place.

Advice to parents: Evaluate your program thoroughly and honestly. Know what all the components are, what is needed, in order for a "model" of action to be effective. If you don't have all the right pieces in place, then be prepared for interventions, patches, band-aids, you-name-it fixes. Or, you may have to bail out of your language immersion program all together and resort to the "old" way of learning a foreign language as... a "foreign" language.