1. A tonal analysis method, comprising: parsing notes of a musical score to generate a time-ordered plurality of sonorities, each sonority having a chord comprising a subset of notes of the musical score based on time value; confirming a plurality of tonal centers each having a tone, each by testing a pair of sonorities among the plurality of sonorities; accounting a chord of a sonority for a confirmed tonal center to determine whether the chord of the sonority is a functional symbol of the confirmed tonal center; and identifying a tonally stable region of the musical score for a confirmed tonal center, wherein the chord of each sonority in a tonally stable region is accounted as a functional symbol of that tonal center.