[0.1.1] As the theories of Heinrich Schenker were gaining currency in the United States in the mid-twentieth century, Milton Babbitt observed that Schenker's theory of voice-leading levels was "strikingly similar to transformational grammars in linguistics" (1965, 60 Numerous generative approaches to explaining tonal structure and/or Schenker's theories have been proposed since Babbitt noted a resemblance between Schenker's analytical method and Chomskian generative grammars in 1965. One of the more challenging features of Schenker's theory to replicate in a generative system is the interaction of counterpoint and hierarchy. Many theorists, such as Lerdahl and Jackendoff, skirt the problem by developing non-contrapuntal systems, meaning ones that do not allow for layers with conflicting hierarchical descriptions.