Words are acoustical signs for concepts; concepts, however, are more or less definite image signs for often recurring and associated sensations, for groups of sensations. To understand one another, it is not enough that one use the same words; one also has to use the same words for the same species of inner experiences; in the end one has to have one's experiences in common.
Basic Writings of Nietzsche (ed. Random House LLC, 2000) - ISBN: 9780679783398