When you are acquiring a language after adolescence (your brain's pathways have changed!), you are a lot more conscious about the various skills that go into acquiring it.
There are four independent skills that you must acquire and it's easy to be proficient at some and deficient at others.
There are two independent axes that can be used to classify them.
- Whether or not you must process the information in real-time.
- Whether the information is internally generated or coming from outside.
- Hearing: real-time and external
- Talking: real-time and internal
- Reading: non-real-time and external
- Writing: non-real-time and internal
The four skills listed above are in descending order of difficulty.
That's the generic theory. Of course, Japanese being slightly unique will mix up the order a little bit. We'll explore that in a later post.