This article is to apply Peirce's theory of "signs" to understand two compositions of Robert Schumann (1810-1856), Papillons op.2 and Carnaval op. 9 as case studies to prove the possibility of building connections between language and music. I use three ways to prove it. First, I define the object of each composition by finding historical evidence of Robert Schumann. Second, I find vertical connections: compare the iconic, indexical, and symbolic signs from both texts and music and examine how they relate to the object; I do so by extracting representational words form the text and representational musical analysis. Third, I form horizontal connections: if the signs from both music and texts successfully indicate the object, I examine the interrelations between each other. The result shows the program, Die Flegeljahre, contains indexical signs that were used by Schumann, indicating the object of Papillons op.2. The object of Papillons op. 2 is represented by the iconic signs in the music. The iconic signs of the music Carnaval op. 9, which resemble the object of the thematic titles, were represented by the iconic signs and symbolic signs in the titles. The music and the program of Papillons op.2 and Carnaval op.9 become the indexical signs that are defined by Schumann. These signs all indicate the final object of both compositions, which is to bring new ideas to German classical music. Thus, the result of the analysis guided by applying Pierce's theories of signs successfully proves that music and language are two domains that can be connected together when the signs of these two domains are used by the same interpretant.