This chapter focuses on the phenomenon of bilingual discourse marking. The introductory part of the chapter provides a definition of discourse markers and discusses their borrowability. Subsequent sections describe the individual discourse marker systems in the core corpus, i.e., Barossa German, Volga German and Blumenau German, and also includes Namibian German and other Russian German varieties. The analysis shows that heritage language speakers use contact-language discourse markers interchangeably with their heritage language counterparts. This is especially true for turn-related particles with a dialogue-controlling function. In this sense, mixed-language discourse marking systems emerge that also contain bilingual markers (i.e., markers that have the same phonological form in both languages). In this domain, the interspeaker variation was extremely high and pointed to rather idiosyncratic dialogue-organizing repertoires. Furthermore, it is demonstrated that the specific system of German modal particles is reduced in heritage communities, and that there is a significant reduction across generations. In the final section, a model explaining the use of different discourse markers by utterance processing is proposed, based on different levels of speech processing. In addition, the section explains individual differences through access to literacy and Standard German.