This dissertation explores middleground functionality of six-four chords by combining a voice-leading approach with hypermetrical analysis. By acknowledging the functional ambiguity of certain six-four chords that do not fit into traditional classifications (Aldwell and Schachter's cadential, consonant, passing, and neighboring six-four), or that can be seen as fitting in more than one category, I show that our interpretation of deeper-level structures is contingent upon how we choose to hear the functionality of these harmonies. Three types of six-four chords are introduced: cadential/consonant, passing/cadential, and neighboring/consonant six-four, illustrated by works by Robert Schumann, Brahms, and Saint-Säens. Each pair refers to an ambiguity—the same chord invites two alternative harmonic interpretations. I call these chords nontraditional in the sense that they shed more light on the musical structure with their ambiguity, rather than when being wedged into a single type of a six-four chord. This approach renews the ways of hearing the malleability of nonconventional Romantic structures and permits us to trace the path of each work as a unique tonal trajectory from a listener's perspective.