  We analyze the occurrence frequencies of over 15 million words recorded in
millions of books published during the past two centuries in seven different
languages. For all languages and chronological subsets of the data we confirm
that two scaling regimes characterize the word frequency distributions, with
only the more common words obeying the classic Zipf law. Using corpora of
unprecedented size, we test the allometric scaling relation between the corpus
size and the vocabulary size of growing languages to demonstrate a decreasing
marginal need for new words, a feature that is likely related to the underlying
correlations between words. We calculate the annual growth fluctuations of word
use which has a decreasing trend as the corpus size increases, indicating a
slowdown in linguistic evolution following language expansion. This "cooling
pattern" forms the basis of a third statistical regularity, which unlike the
Zipf and the Heaps law, is dynamical in nature.
