Imagine that you were an archeologist examining a site close to the place where you grew up or where your parents grew up. Imagine you find a thousand years old sheet of paper and on that site of paper you see your own damn handwriting and drawings depicting the most important moments of your life that have indeed taken place! Those drawings include such intimate details that there cannot possibly exist anyone else but you who could know about them. Some of those details are so intimate that you would not even be able to verbalise them, or did not even realise them yourself until you saw them. You feel like the person who did that drawings knew you better than you know yourself, what is more, in some weird way this person seem to have been you.
I have exactly this feeling when I a now revisiting my old German schoolbook. I see where I made annotations, to which words, where I was confused, I look at the diagrams of German sentences and I am shocked. Because this was the only book from which I actually learned the language, it is easy to conclude that all my current knowledge of German has its blueprint in the times when I was learning from that book. When someone says certain German words to me I see in my mind a written annotated translation - and now I saw what I usually see in my head, I saw the very same annotation in that freaking book, made by myself, years ago! The way how I understand construction of sentences - I flip the page and I see my internal mind picture freaking printed in the book! That is such a funny feeling, that goes: "how did they know what is in my head and how the hell were they able to print it X years ago?!". But it is not that way, it is the other way round. When I was learning from that book I just memorised those pictures so deeply that it become part of my implicit knowledge. I memorised the content but I completely lost the information of where this content came from. I thought I made it. I didn't make it, I took it.
Now think about this: what if we humans do it with other things too?
And hell yes, we do! This is connected a bit with what I wrote in this post about thunderstorm and car oil. It is so easy to internalise early experiences and treat them as "ours", as something that we came up with ourselves. A kind of inception effect. It must have been so easy to brainwash us as children. That is why dysfunctional families leave such a deep wounds and issues in its children.
I really recommend trying to take some old schoolbooks, notepads, and check how your current mindset is a reflection of what was already happening years back. Watch some old videos if you have ones. It could give you the feel of what it means "to internalise". Children also internalise the nagging and demanding parent, they internalise the scolding, they internalise things that later make their lives unliveable. And in the end they blame themselves for it as they think that it must be coming from them. In many cases you may discover that no, you didn't make it, you only took it. That's the point of recovering from CPTSD, to recognise and reject the brainwashing. To wake up from the matrix, with no pill, by yourself.