But a spoken language in its development is progressive as well as
conservative. To certain modifying influences it is especially sensitive.
It is fond of the concrete, picturesque, and novel, and has a high
appreciation of humor. These tendencies lead it to invent many new words
and expressions which must wait months, years, perhaps a generation,
before they are accepted in literature. Sometimes they are never accepted.
The history of such words as buncombe, dude, Mugwump, gerrymander, and
joy-ride illustrate for English the fact that words of a certain kind meet
a more hospitable reception in the spoken language than they do in
literature. The writer of comedy or farce, the humorist, and the man in
the street do not feel the constraint which the canons of good usage put
on the serious writer. They coin new words or use old words in a new way
or use new constructions without much hesitation. The extraordinary
material progress of the modern world during the last century has
undoubtedly stimulated this tendency in a remarkable way, but it would
seem as if the Latin of the common people from the time of Plautus to that
of Cicero must have been subjected to still more innovating influences
than modern conversational English has. During this period the newly
conquered territories in Spain, northern Africa, Greece, and Asia poured
their slaves and traders into Italy, and added a great many words to the
vocabulary of every-day life. The large admixture of Greek words and
idioms in the language of Petronius in the first century of our era
furnishes proof of this fact. A still greater influence must have been
felt within the language itself by the stimulus to the imagination which
the coming of these foreigners brought, with their new ideas, and their
new ways of looking at things, their strange costumes, manners, and
religions.

The second important factor which affects the spoken language is a