Whatever time frames you apply, the only way to really learn a language is to use it. Reading a book, blog articles, and watching videos on YouTube won't give you the hands on experience necessary to internalize how everything works.

Of course. My methodology is usually this:

Day 1: read the introduction of a book, set up editor and environment

Day 2: (superficially) learn flow control and type system

Day 3: practice with coding problems on codewars

Day 4-7: reimplement one of my projects

Week 2: read the second quarter of the book and continue with puzzles

Week 3+: Just projects, maybe invest a day into tooling somewhere in between

That is assuming 1-3 hour days

> read the second quarter of the book

And then never get to the third and fourth quarters because the practise you get from actually typing stuff is far more valuable? :)

Exactly. There usually is some stuff about the deeper, darker corners of a language in the type of book I pick.

I usually pick the authoritative book / advanced book. Think "Programming PHP", "The joy of clojure", "The C Programming Language", etc. I don't necessarily need to know all about performance optimization, the async model or non-html templating.

Reading a technical book cover to cover feels wasteful imo

True, but actually reading a book about the language to understand the philosophy behind it and its trade offs speeds up the process enormously.

The way to become good at something is to do it for a long time and to be willing to think about what you are doing and continually improve.

There's much more to learning a language properly than just learning the language spec itself. Especially if we're talking about languages such as Java, where you have to know quite a bit about how the runtime works in order to be able to make good design decisions. And Go isn't really that simple either when we start to get into the weeds of performant concurrent systems that also need to be robust. It requires quite a bit of work to be able to make full use of what Go offers. It may look simple, but concurrency never is.

You're essentially arguing in favor of not being good at what you do, or at best being mediocre at lots of things. And I'm sure there are lots of jobs where that is okay. The thing is: why would you want to spend a lifetime being mediocre, to work on mediocre projects with other people who are mediocre?