s system may be said to be primarily adapted to the
movements made in walking and in similar activities. In a very real
sense the normal human being is predestined to walk, not because his
elders will assist him to learn the art, but because his organism is
prepared from birth, or even from the moment of conception, to take on
all those expenditures of nervous energy and all those muscular
adaptations that result in walking. To put it concisely, walking is an
inherent, biological function of man.

Not so language. It is of course true that in a certain sense the
individual is predestined to talk, but that is due entirely to the
circumstance that he is born not merely in nature, but in the lap of a
society that is certain, reasonably certain, to lead him to its
traditions. Eliminate society and there is every reason to believe that
he will learn to walk, if, indeed, he survives at all. But it is just as
certain that he will never learn to talk, that is, to communicate ideas
according to the traditional system of a particular society. Or, again,
remove the new-born individual from the social environment into which he
has come and transplant him to an utterly alien one. He will develop the
art of walking in his new environment very much as he would have
developed it in the old. But his speech will be completely at variance
with the speech of his native environment. Walking, then, is a general
human activity that varies only within circumscribed limits as we pass
from individual to individual. Its variability is involuntary and
purposeless. Speech is a human activity that varies without assignable
limit as we pass from social group to social group, because it is a
purely historical heritage of the group, the product of long-continued
social usage. It varies as all creative effort varies--not as
consciously, perhaps, but none the less as truly as do the religions,
the beliefs, the customs, and the arts of different peoples. Walking is
an organic, an instinctive, function (not, of course, itself an
instinct); speech is a non-instinctive, acquired, "cultural" function.

There is one fact that has frequently tended to prevent the recognition
of language as a merely conventional system of sound symbols, that has
seduced the popular mind into attributing to it an instinctive basis
that it does not really possess. This is the well-known observation that
under the stress of emotion, say of a sudden twinge of pain or of
unbridled j