Collaborative learning with recorded lectures and presentations can be supported by allowing users to anchor notes in the documents and exchange them with other learners. While the traditional modality for annotation and discussion is text, there are a number of reasons in favour of supporting other media and modalities as well. We describe the extension of a lecture-on-demand annotation and discussion system that allows learners to use spoken notes. Our main focus is on the development of a suitable user interface that facilitates the retrieval of speech data employing signal-processing algorithms while at the same time being simple and easy to use.