Yeah, there are many particular situations that could be researched in detail, and it seems reasonable that different areas of a language have different optimal spacing, which might also be different between individuals. There’s clearly an upp boundary to how much learning one can do, even if relying mostly on comprehensible input and engaging content, and equally clearly, there’s a point beyond which spacing things out further decreases efficiency.

I think terminology is interesting, because there is of course a difference is how normal people use words and how people who spend most of their time with a subject use words (hence professional jargon, etc.). However, when writing for the general public, I try to avoid using words that have very specific meanings, so even if this article is about efficiency, effectiveness and speed, I also use this somewhat interchangeably in other contexts. The same goes for errors and mistakes, which I think are fundamentally different, yet people normally don’t use them with such clear distinction. Another one might be whether or not to use a word like “radical” to mean what most people think it means, or to mean what it actually means. Tricky!

I tend to use efficiency and speed interchangeably when I write, as generally the effective approach is so by virtue of the learning accomplished per unit time. Thus, the person who learns the fastest with 100 hours is generally going to be the person who learns the most efficiently.

The main places I think the concepts diverge is (a) spacing, where the same hours over a longer schedule look less impressive in the near-term, but result in faster forgetting and (b) learning fundamentals, like character components or tones, can be practically avoided in the early phases, but end up creating obstacles later if you try to advance.

What do you need help with?