Which method to choose?

The basic idea is that, to be a good teacher, you have to be aware of what kind of difficulties the students face in their attempt to learn a foreign language.
But, one open question is ... should teaching be provided 100% in the target language, or it’s possible to use the L1, or anyway a “lingua franca”, to give explanations?

Let’s imagine first a multilingual, multiethnic class, in which it’s not even possible to find a lingua franca. This often happens with immigrants, and at the very beginning it can put the teachers in trouble. Obviously in this case is L2 the only possible teaching language. On the other hand, immigrants have an advantage. They are continually exposed to the language they are trying to learn. It’s all around them unless they lock themselves in their homes, switch on the TV and find a channel in their own language. But, if they have a job, or run errands, go grocery shopping, or listen to the local news, they are training their speaking and listening skills.

But people who study a L2 in their own country, who don’t have a chance of practice outside of class (if they are in a class), or are autodidacts who study alone, have a hard time if they don’t get some explanations in their own language, or at least in a lingua franca.

For example, I learned Swedish on my own (after having tried a few lessons in a sort of amateurish class), and the first thing I did, since what I read in the 100% Swedish textbook I had bought was as clear as mud, was to download material in English.
After learning the very basic of the language, I signed up to a Swedish chat site, and started exchanging messages, very simple at first, then step by step more complex. Then with the help of providers such as Skype, or Yahoo, it was possible to try short conversations. I was feeling confident, since whenever I was unsure of how to say something, or something was unclear to me, I would look it up in my “English-Swedish” textbooks and find an answer.

This has, however, nothing to do with the pedantic teaching-learning methods of the past, with a long list of rules and names to learn by heart, completely detached from the “language as it’s really spoken”.

It’s widely debated, nowadays, if we should even be using grammar books. Even bringing up the debate over grammar is heading into a minefield. I understand that it’s important to get away from the boring, pedantic, scarcely effective deductive methods of a few decades ago, but I have yet to understand why grammar should be seen as a freak or, at most, as a potentially venomous medicine to be dispensed only in drops (the fewer, the better). Why can’t it just be seen as an ally, a support for the students?

Inductive methods are great, there is no doubt about it, when they work. The change in methodology started from England, and English is not as structured a language as Italian (in tenses, moods, conjugations) though very complex its own way.
English leaves much more space to induction, or rather instinct, than, say, German or Italian. And, without making the mistake of considering English grammar as “simple”, we can without any hesitation state, that the listening skill is the hardest to improve, even for experienced students. (students of English as L2, however).
In my opinion it would be very childish, if not irresponsible, to passively ape the changes English teaching methodology has brought about. I can’t believe my eyes when I see schools which vaunt their 100% “in Italian” teaching”.
Students coming from all over the world for a 2-3week class, pay an arm and a leg, and often end up disappointed, if not frustrated. I have had a few of them, who admitted to being left behind. They complained that teachers kept their pace, regardless of whether students could keep up or not.
However, we shouldn’t forget that a teaching method, as far as possible, should be tailored on students’ needs and targets.