Many people's entire thought process is an internal monologue. You think that voice is magic? It takes input and generates a conceptual internal dialogue based on what it's previously experienced (training data for long term, context for short term). What do you mean when you say you understand something? What is the mechanism that your brain undergoes that's defined as understanding?

Because for me it's an internal conversation that asserts an assumption based on previous data and then attacks it with the next most probable counter argument systematically until what I consider a "good idea" emerges that is reasonably vetted. Then I test it in the real world by enacting the scientific process. The results are added to my long term memory (training data).