We now have a sense of how Janáček's musical style developed: his early predilection for motivic designs was transformed through his incorporation of folk elements and found its natural home in twentieth-century contexts. The rhythmic freedom he felt instinctively and interpreted as a reflection of real life was reinforced by attention to his native folk repertoire. His collected speech melodies inspired freer, more realistic melodic lines and contributed to the loosening of rhythmic structures, promoting an individual manipulation of motivic details. Although Janáček's music always maintains a tonal basis, his continual attention to contemporary musical developments advanced its harmonic and rhythmic inventiveness, a characteristic particularly noticeable in his final creative period.

Janáček's music does not follow predictable patterns, often surprising us with its originality; indeed, one may wonder whether Janáček was a systematic composer. Although he did approach certain tasks systematically—for example, his study of theoretical treatises or the works of other composers— his music contains inconsistencies that avert extensive systematization and suggest improvisational practice. Although he evidently saw the need for logical structures, his imagination could not limit itself to predictable, established patterns. The music contains a kind of paradox: many passages are highly repetitive, but constant variation avoids certainty and predictability.

The early years of the twentieth century saw similar characteristics in the music of other eastern European composers, notably Béla Bartók and Igor Stravinsky. They too turned to folk music for ideas and inspiration (Bartók acknowledging that fact more readily than Stravinsky) and blended its elements with modernism in their individual musical languages. Though both were nearly thirty years younger than Janáček, he became familiar with their music in his last decade and acknowledged their contributions.

Awareness of Bartók probably came from Schoenberg's Theory of Harmony, a book Janáček studied in 1920. His annotations show a particular interest in “Chords constructed in fourths” and “Chords with six or more tones,” chapters that mention Bartók and provide an example from his Fourteen Bagatelles, op. 6.