Sentence:  The human world is contracting not only prospectively but to the backward-probing eye of culture-history. Nevertheless we are as yet far from able to reduce the <WSD>riot</WSD> of spoken languages to a small number of "stocks". / "In summer this flower garden is a <WSD>riot</WSD> of colour." 
Meaning of the word marked with <WSD> tags:  A wide and unconstrained variety.