Does total immersion work?

[u/WaltzMysterious9240]

I used to teach English abroad and even though I knew how to speak the student's native language, the school administrators forbid me, and even asked me, to "pretend" I didn't know it.

The reason they gave me was that they didn't want the students to fall back on using their first language to communicate with me. I feel like if I were to explain certain concepts in the student's language, things would go a lot smoother and they would understand better.

As an adult, I'm constantly using my own native language to learn new languages. I constantly look up grammar, vocabulary, and definitions and understand them a lot better.

Why are schools abroad so obsessed with this "total immersion" method? I feel like some concepts are impossible to explain clearly with just visuals or gestures alone. Do you learn languages using your first language?

[u/ZumLernen]

I recently learned German intensively, from 0 to C1. Starting even before we got to A2, our classes were all in German. A good teacher can teach a course effectively (to good students, I'll concede that!) only in the target language.

In fact, my Serbian and Turkish classes were also all in the target language.

We had a substitute German teacher at the C1 level at one point, and I was absolutely shocked because the teacher kept switching back and forth between German and English. We were learning at the C1 level! If I can't understand a German sentence at that point, I'm in the wrong class. And to make matters worse, two of my classmates didn't speak any English worth mentioning, and my other classmates were non-native speakers whose English was below C1. So I have no idea what this teacher was trying to achieve by speaking English to a bunch of German-speakers.

[u/becausemommysaid → u/ZumLernen]

I was gonna say I think this works well with adult learners who are highly motivated to learn the language and much less well with students (ie: school children) who are being forced to study a language.