Sumo Introductions, Music?

An assortment of sumo wrestler introductions at the Japanese Grand Sumo Tournament filmed on 5 February 2012.  Introductions are handled by the same people who sweep and maintain the ring in between bouts.  Each person introduces about 5 bouts and then trades out with a new introducer.

The introductions caught my eye because they are rather musical in nature.   The tones and general rhythm of each introduction follow a precise patern, but small variations can be heard amongst each individual.  Most examples of traditional Japanese music place focus on the voice as the primary instrument and this often extends to forms of narration such as the Tayu of Bunraku plays, so it is not too surprising to find the voice used in such a musical manner.