I'm reading The Rough Guide to Classical Music (2010 5th ed.) by Joe Staines. On p. 563 bottom, left column, he writes:
Takemitsu’s orchestral works vary considerably, but his overriding preoccupations – sonority and slow-paced musical unfolding – are ever-present. In November Steps (1967) an almost competitive dialogue between the Japanese instruments takes place well in front of the orchestra, which ebbs and flows in and out of the soloists like a multi-voiced and eloquent chorus. The language is gestural and splintered (not unlike Boulez), greatly increasing the overall impression of highly coloured abstraction.
What does the bolded phrase mean? What do "language", "gestural", "splintered" mean?
How does such "language" of Takemitsu's mirror Boulez's?
How does "gestural and splintered" "language" increase "the overall impression of highly coloured abstraction"?