Having a vital role in organizing conversational interaction, discourse markers (DMs) are considered to be a significant part of communicative competence. From a Relevance Theoretic perspective and combining insights from corpus linguistics and second language acquisition research, this study is an attempt to explore how non-native speakers of English (NNS) use the DMs in their spoken language. Following the framework of Contrastive Interlanguage Analysis (CIA), this study is based on two specific corpora: Turkish sub-corpus of The Louvain International Database of Spoken English Interlanguage (LINDSEI-TR) for NNS speech and The Louvain Corpus of Native English Conversation (LOCNEC) for native speech. The occurrences of DMs in both corpora were determined using inferential and descriptive statistics. The findings of the study are discussed in connection with implications for language practitioners and syllabus designers in the field of language teaching.