Apprehensionality refers to the semantic domain of negative prospective epistemic modality and the formal expressions used to encode it. In this article, we break down the apprehensional situation into five prototypical components: (I) future reference, (II) possibility, (III) negative evaluation, (IV) avertive intent, and (V) a preferred action. In doing so, we propose a framework for comparing synchronic and diachronic aspects of the semantics and expression of apprehensional modality across languages. We discuss several recent formal accounts of three apprehensional morphemes—Francez's account of Biblical Hebrew pen, Dąbkowski and AnderBois's of A'ingae ‐sa'ne, and Phillips's of Australian Kriol bambai—relate their formalisms to the apprehensional situation schema, and evaluate their predictions. We summarise previous findings on the grammaticalisation pathways towards and among apprehensional morphemes. We find that apprehensionals grammaticalise from a wide range of sources, including components I–IV of the apprehensional schema. Among the apprehensional functions themselves, both subordination and insubordination are commonly encountered.