[aix1]

> The talking improves almost automatically, without having to practice it.

I absolutely don't doubt your experience, but find it interesting that mine has been the exact opposite.

I listen to a lot of German and read a fair amount. As a result, my listening and reading comprehension got pretty good (at least B2). My writing has also improved significantly (probably also around B2). However, I find that this does not transfer well to speaking, which I need to practise separately in order to see a meaningful improvement. After some targeted lessons I'm just about approaching B1.

Perhaps transferability will improve once I reach a certain level of fluency. I think this might have happened when I was learning English. However, this was so long ago that I no longer remember.

For the next language I might try to overemphasise speaking from day one just to see how the learning trajectory differs.