  Studies of the overall structure of vocabulary and its dynamics became
possible due to creation of diachronic text corpora, especially Google Books
Ngram. This article discusses the question of core change rate and the degree
to which the core words cover the texts. Different periods of the last three
centuries and six main European languages presented in Google Books Ngram are
compared. The main result is high stability of core change rate, which is
analogous to stability of the Swadesh list.
