Final answer:
Richard Wagner's musical language was based on chromatic harmony.
Step-by-step explanation:
Based on the information provided, the composer whose musical language was based on chromatic harmony is Richard Wagner. Wagner was a leading figure in the Romantic era and is known for his innovative use of chromatic harmony in his compositions. His music often features complex harmonies and lush orchestration that pushed the boundaries of traditional tonality. Some of his notable works include the operas 'Tristan und Isolde' and 'The Ring Cycle.'