Figure 6. Dynamical behavior of P- and S-words in time.
A, B, Number of occurrences of example P- and S-words as a function of the center 
of each half-year window. Example words: P-word gnome, a software product; S-word lol (“laughing out loud”); P-word eminem, a rapper; S-word iirc (“if I recall correctly”). The curves are normalized by the maximum number of occurrences per window reached over all windows: 
for gnome and 
for lol (A); 
for eminem and 
for iirc (B). C, D, Total number 
of all words in each half-year window centered at 
.