Have You Heard of Reflective Writing?
Writer's Wisdom: Is writing merely a tool for expression and communication? In recent generations, writing has been recognized for its role in 'organizing thought'. A brief look at our sages' words reveals that this is not a new phenomenon.

We typically regard writing as a means of preserving information long-term or communicating ideas from one person to another. Surprisingly, writing also plays a crucial role in the thinking process itself. This innovation, known as 'reflective writing' in recent generations, was already noted by the Maharsha in Tractate Bava Batra (10b), where he wrote: 'The primary study that leaves an impression is that which comes from handwriting. Therefore, sages are called "scribes."' In other words, the Maharsha sees writing as a form of learning. How does writing practically serve as a tool for thought? When an idea exists only in the writer's mind, it remains unclear and vague. However, once expressed in writing, it creates information that returns to the brain like a reflection. The writer gains a new, clear perspective on the subject, adding depth to the matter, and can easily evaluate the truth of their words. This is why when required to solve a complex problem, we reach for a pen to sketch out the calculation.
An interesting explanation for this phenomenon is suggested by the Gaon Yaavetz zatzal in his book 'Migdal Oz' (The Rise of Writing, page 151, section 12): 'With writing, a person can recognize an error or lack of completeness by seeing it with the eyes and understanding it in the heart before it is released from his hand. He will better notice where correction is needed, examine cracks and fissures, and strengthen, smooth, and polish them. This is not the case with things in the heart, where vision does not dominate. One cannot as easily spot the error or obstacle to fix it adequately after it comes out of the mouth, and what's bent cannot be straightened. Therefore, our sages insisted that written matters should not be spoken orally.' The addition of the sense of sight to the sense of speech, according to the Yaavetz, drives the content deeper into the mind.
Therefore, Maran HaGaon Rabbi Meir Mazuz shlit"a advises in his book 'Darkei Ha'iyun' (Essay 2, section 27): 'When testing yourself to see if you've accurately understood the words of Tosafos and the commentators, do this: Try to write down what you understood orally on a sheet of paper, and then check if your words match the language of the Tosafos and the commentators. If the arrangement is right and the differences are only in the expansion and repetition of words, that's good. If not, it's a sign you haven't understood, and you should return and study thoroughly, because writing is a testing ground to reveal if the understanding is correct.'
It's also reported that when students told Rabbi Chaim of Brisk zatzal that they could not express a complex thought, he would tell them: 'Until an idea is expressed, it doesn't exist.' Moreover, he is quoted as saying: 'If someone lacks in expression, it indicates they lack in understanding.' Therefore, it is advisable to put the idea in writing before presenting it to others.