Everyone knows that full immersion is the absolute best way to learn a language, right? Ideally, we all want to learn a language the way native speakers learn it, so that our own language doesn’t conflict with our new language. We want to pick it up naturally, like a baby. That’s what most English conversation schools are offering with their foreign teacher lessons. That’s what Rosetta Stone says they’re offering.
And all of that makes for very fine marketing to people who don’t actually know much about learning a languages. Adults have big, well-developed brains full of excellent analytical skills, and it’s a waste not to use that expensive hardware toward a cognitively demanding task like language learning. It’s possible to learn a language without using your native language, but it’s not necessarily the best way. Adults have skills that children don’t, and trying to learn like a child means ignoring a lot of your ability to reason through a foreign language using your first language. If you want to learn Korean, then you shouldn’t try to emulate the learning environment of a Korean baby–although, if you can convince a Korean woman to breast feed you and use motherese on you, you might have the start of an interesting research project.
That’s why I have used and will continue to use Japanese in my English classrooms. My students come to my classroom with decades of linguistic knowledge already piled up in their heads, and most of it is really useful for learning English. They have to learn how to integrate that knowledge into a new, bilingual language system, one that is both distinct from their native language and from the English of monolingual native speakers. Teaching a language means teaching a person to be bilingual. Bilingual people code-switch, code-mix, translate, and negotiate the language(s) of interaction. To deny this is to deny some of the most fundamental aspects of cross-lingual and cross-cultural communication.
In a more concrete, less theoretical sense, I cannot teach Japanese people to speak English without teaching them how to use their knowledge of Japanese in the course of using English. They absolutely must learn how to introduce Japanese words into an English conversation, because we don’t have words for enoki mushrooms or okonomiyaki in English, and they will embarrass themselves terribly if they think they can’t communicate with someone unless they use an English word. My students must learn when it is appropriate to code-switch and introduce Japanese words into an English conversation. Every English-speaker living in Japan uses the word shinkansen to refer to bullet trains, but few people outside of Japan use that word, and my students need to know when that’s appropriate.
Moreover, some forms of advanced organizers are better delivered in their native language. Often, declarative knowledge precedes procedural knowledge, and it’s helpful for us to be able to communicate quickly and clearly. It’s a massive waste of my students’ time for me to explain the articulatory mechanics of English pronunciation in English, but it’s insanely valuable for me to give them a basic crash course in Japanese. I have a short routine to explain how to differentiate /r/ and /l/ sounds to nearly any Japanese audience, and I can usually get them to pronounce the sounds passably in under three minutes. I can’t do that in English.
The students’ L1 is a potent tool that every teacher should have in his toolbox, if possible. It’s not the right tool for every job, but it very often can facilitate a lot of learning, especially in terms of presenting advance organizers that will help students to understand the rest of the lesson. Most of all, my students know that they can ask me a question in English or Japanese, if they need to, and I’ll use every resource I have to help them learn.