This study seeks to describe the discourse structures when Swazi English as Second Language (ESL) Grade 3 students produce English oral and written narratives. The third graders were typically developing children (TD) and were asked to perform two language tasks. They had to speak and write in English based on a less used wordless cartoon entitled "The boy who learned to fly, Usain Bolt". ELAN software was used to transcribe and code samples of oral language. The findings were that, both oral and written narrative discourse production had similar narrative structures. However, the differences emanated from the linguistic structures. The written narrative discourse productions were compressed, laden with ungrammatical language and phonetic spelling while oral narrative discourse productions were long, used code-switching, direct speech, contractions, and repairs. Furthermore, the differences in the linguistic discourse structures have a great connection with the students' varying achievement levels. The implications of these results are that language practitioners/instructors need to help language learners get acquainted with language used in the spoken and written modalities, particularly the middle and lower achievement categories. This could be achieved by focusing their teaching on language forms and provide the learners with proper contexts in which these modes can be used appropriately in English language for academic success.