"The development of articulate language takes place in the period between the age of two and the age of seven: the age of perceptions in which the attention of the child is spontaneously turned towards external objects, and the memory is particularly tenacious...It is well known that it is only at this age that it is possible to acquire all the characteristic modulations of a language which it would be vain to attempt to establish later."  Maria Montessori, The Montessori Method, Chapter 18, p.315, Schocken Books, Inc., 1964.