George Macdonald said this quote
“ When I learn the meaning of a word, I know the word; but when I say to myself, 'I know the word,' there comes a reflection of the word back from the mirror of my mind, making a second impression, and after that I am at least not so likely to forget it...“When, then, I think about the impression that the word makes upon me, how it is affecting me with the knowledge of itself, then I am what I should call self-conscious of the word—conscious not only that I know the word, but that I know the phenomena of knowing the word—conscious of what I am as regards my knowing of the word. ”