This paper looks at the demotic tongue of mateship in Australian Great War Literature as a theme of cognition and understanding in the literary texts and texts of culture. The language, like the Australian, was filled with character and a sense of the larrikin. It seemed irreverent at times, even rude in some circles, but it was much more than its immediate sound or inference; it was the natural verbal essence of the Australian mind – honest, loyal, dutiful and humorous. These characteristics are cornerstones of Australian mateship, a type of friendship that would be there beyond the bitter end, rival the love of a woman and even the protection of one's own life. For some Australians, poetry was merely an extension of this language, as language was merely an extension of friendship. The aim of this paper is to demonstrate the Australian use of humour and language in the setting of Great War poetry. It looks at the demotic tongue of mateship, specifically what is known as the Great Australian Adjective (bloody), along with several other examples of vernacular language, in Australian Great War Literature, and considers this by referring to the common language of the Australian poet from the time. It will consider the notion that Australian writers of the Great War era may have been misunderstood as a result of their language, leading to critical mistakes about a poem's literary worth, a poet's seriousness as a poet and a nation's literary value.