English: (a) Examples of the rank-frequency distribution (relative frequencies z′ such that ). For ease of visualization, curves are chronologically shifted by a factor of 10 in the vertical axis. Some frequent and infrequent codewords are shown. (b) Examples of the density values and their fits, taking z as the random variable. Curves are chronologically shifted by a factor of 10 in the horizontal axis. (c) Average shortest path length l versus clustering coefficient C for pitch networks (right) and their randomized versions (left). Randomized networks were obtained by swapping pairs of links chosen at random, avoiding multiple links and self-connections. Values l and C calculated without considering the 10 highest degree nodes (see SI). Arrows indicate chronology (red and blue colors indicate values for more and less recent years, respectively).