This study uses Systemic Functional Linguistics (SFL) as its theoretical framework to investigate the thematisation of Wapan ideophones. Thirty (30) were purposely collected and analysed using descriptive qualitative methodology, both gathered through participant observation and Wapan videos on Facebook. The results revealed that simple unmarked themes are the prevalent themes, followed by unmarked multiple themes; simple marked and multiple marked themes are less prevalent. The study also revealed that Wapan expressions are highly ideophonic in nature, and the ideophones have great variations. The study contributes to knowledge by giving insight into how simple or multiple themes can be marked or unmarked with an ideophonic expression showing emphasis, intensity and description. This study is projected towards the standardisation of the Wapan dialect. The study will be useful as a resource for schools and other groups interested in promoting local languages. Studies such as this are tremendously valuable to linguists interested in developing minority languages, particularly those that are endangered or facing possible extinction.