This paper presents a preliminary analysis of the role of some discourse markers and the vocalic hesitation euh in a corpus of spoken human utterances collected with the RITEL system, an open domain and spoken dialog system. The frequency and contextual combination patterns of classical discourse markers and of the vocalic hesitation has been studied. This analysis highlights some specificities in terms of combination patterns of the analyzed items. The classical discourse markers seem to help initiating larger discursive blocks both at initial and medial positions of the ongoing turns. The vocalic hesitation also stand for marking the user's embarrassments and wish to close the dialog.