Compounds, i.e. concatenated words, were shown to be decomposed morphologically/morphosyntactically during comprehension. Hence, the morphosyntactic feature (gender) of constituents is processed as part of the morphological representation. Number, an important morphosyntactic feature in general, is not specified for initial constituents, but only for the head (in German the final) constituent of a compound. Linking elements between constituents are often phonologically identical with plural morphemes. Whether prosodic cues are used to disambiguate these elements was tested in an event-related potential (ERP) study. Subjects heard acoustically presented critical items that were produced naturally as single nouns or initial compound constituents. These were preceded by a number marked indefinite determiner. Half of the single nouns were singular forms, the other half were plural forms. Half of the compound constituents contained linking elements, the other half did not. Subjects had to detect incongruities between determiners and critical items. Any possible bias of stimuli to be perceived as single nouns or compounds was prevented by appropriate filler items. Single nouns and compound constituents differed in the prosodic parameters duration and pitch (contour). Number violations of single nouns were detected online as indicated by a posterior negativity in the ERP. "Number violations" of compound constituents did not yield any effect until 500 ms past the effect for single nouns; the negativity for incongruent compound constituents showed an anterior scalp distribution. Thus, prosodic cues permit the parser to differentiate phonologically identical plural morphemes and linking elements in order to refrain from irrelevant morphosyntactic operations.