Task: Question Answering
Input (English): Passage: American music critic and journalist Harold C. Schonberg wrote of Tchaikovsky's "sweet, inexhaustible, supersensuous fund of melody," a feature that has ensured his music's continued success with audiences. Tchaikovsky's complete range of melodic styles was as wide as that of his compositions. Sometimes he used Western-style melodies, sometimes original melodies written in the style of Russian folk song; sometimes he used actual folk songs. According to The New Grove, Tchaikovsky's melodic gift could also become his worst enemy in two ways. The first challenge arose from his ethnic heritage. Unlike Western themes, the melodies that Russian composers wrote tended to be self-contained; they functioned with a mindset of stasis and repetition rather than one of progress and ongoing development. On a technical level, it made modulating to a new key to introduce a contrasting second theme exceedingly difficult, as this was literally a foreign concept that did not exist in Russian music. The second way melody worked against Tchaikovsky was a challenge that he shared with the majority of Romantic-age composers. They did not write in the regular, symmetrical melodic shapes that worked well with sonata form, such as those favored by Classical composers such as Haydn, Mozart or Beethoven, but were complete and independent in themselves. This completeness hindered their use as structural elements in combination with one another. This challenge was why the Romantics "were never natural symphonists". All a composer like Tchaikovsky could do with them was to essentially repeat them, even when he modified them to generate tension, maintain interest and satisfy listeners. 
Question: What is the name of the person who sometimes used original melodies written in the style of Russian folk song?
Output (English): Tchaikovsky.