progress of opinion by word of mouth at an immeasurable 
     distance behind. Two or three generations of literature 
     may do more to change thought than two or three 
     thousand years of traditional life. . . . and so it has come 
     about that in Europe at the present day the superstitious 
     beliefs and practices that have been handed down by 
     word of mouth are generally of a far more archaic type 
     than the religion depicted in the most ancient literature of 
     the Aryan race. . . .”

     Just how this comes about is the theme of Iona and Peter 
Opie in their Lore and Language of Schoolchildren  (pp. 1­2):

     While a nursery rhyme passes from a mother or other 
     adult to the small child on her knee, the school rhyme 
     circulates simply from child to child, usually outside the