That's interesting. I have a somewhat similar problem. Often, I forget the words I was trying to say and then have to describe it with vocabulary of elementary school level, if even. This is only the case when talking, not writing. For example: I forget the word "butterfly" and say something like "cute fly thing" or look at a carrot, say "potato" and don't realize unless someone corrects me. Sometimes it feels like I black out and don't even know the "big word" anymore. I'm curious, do you also experience this or do you not have issues remembering words you want to say?