Abstract Despite 4QMMT having been informally called a “Halakhic Letter” since its first publication, more recently some scholars have expressed skepticism as to the original genre of this text. This article aims to provide empirical and theoretical support for what one might call the orthodox position: that this text was in fact a letter originally. By means of a detailed linguistic comparison between 4QMMT and the Damascus Document, it will be shown that despite many surface similarities between these texts in terms of structure and rhetoric, they present extremely divergent grammars. This in turn raises a fundamental question: how could two texts likely produced by the same community be so different linguistically? It will be argued that the most plausible explanation is that these two texts were written in distinct registers in order to accommodate to distinct literary genres. While the language of MMT can reasonably be called closer to the contemporary vernacular, the Damascus Document seems to be patterned after the language of the higher register of biblical narrative. From here, sociolinguistic research will be employed in an effort to show that the epistolary genre reliably reflects a lower register across languages and cultures, thereby justifying the orthodox position with respect to MMT.