His original style that has already manifested in the early 1920s, was often characterised as a combination of expressive colouring, intense lyrical qualities and prolific melodic inventiveness with the ideal clarity, aristocratic elegance and precision of structure. French, Belgian, Dutch, German, Austrian, Italian and American critics praised his mastery in orchestration, instrumentation and the use of orchestra, and pointed to his sophisticated music language, including such of his trademarks as his individual approach to form, where he introduced the so-called "bridges", and the chord called "the skyscraper".