I was listening to a podcast where he discussed the concept of learning by doing. I think he is right. One of the most effective methods for learning anything is through hands-on experience. For example, if you want to learn programming or human language, you must practice or do it.
The second way is observation. Remember, when you visit a motorbike or car mechanic, young interns are merely observers. They are helpers, but they learn with observation. How are others doing? You observe and then do. Children learn anything from their parents. I continue to learn from my experiences and from the actions of others.
Teaching is the third method. If you want to learn any subject, start teaching it. When you are explaining anything to others, our minds think in different ways. Do you remember the rubber duck method? When you are unable to solve your programming problem, use the rubber duck method. Pick a rubber duck and start explaining it to him. Your mind solved the problem.