Notker's short five-section treatise De musica was written exclusively in Old High German, except for the retention of technical terms in Latin and pseudo-Greek, with De mensura fistularum organicarum being the last. In De musica Notker abandoned his practice of giving the Latin text before each part of the German translation, for the discourse was no doubt intended as a manual for organ builders, of whom Latin could not be required. In this study relevant passages from the Latin texts alternate with Notker's translation. Then the four manuscripts preserving the fifth section in full or in part are compared in their fidelity to Notker's accentuation and allophones of initial consonants. Finally, the twelve terms retained in Latin and pseudo-Greek are enumerated.