Research the theory

Theories, hypotheses, laws, principles, axioms, maxims . . . Just think of them all as ideas. People get ideas about . . . oh . . . learning languages, for example. And those words are just different ways of saying 'idea' depending on how much backing a particular idea has, or how well people agree on how it works.

Regarding our understanding of how the brain learns language, no one can say exactly. There are different ideas.

Now that's important--the fact that there is/are a number of ideas. This means that you have a choice. Which suggests that you don't simply fall into a pattern of studying language without considering at least a few of those options.

So give yourself a choice. Read a book or two. Explore the Internet using a few select keywords. Do some research.

You may even come up with an idea of your own!