1. A computer program product, comprising: a computer readable storage medium having program instructions embodied therewith, the program instructions readable by a processing circuit to cause the processing circuit to perform a method of determining a crowd behavior, the method comprising: collecting, at one or more recording points in a crowd of individuals, audible expressions that the individuals of the crowd make; generating a graph of the audible expressions as the audible expressions are collected from the individuals; determining a crowd behavior by performing a graphical text analysis on the graph; and outputting an indication of the crowd behavior to trigger a crowd control measure.