This article focuses on a non-canonical use of negation in historical and modern French, characterized by an apparent absence of meaning: expletive negation. In search of the lost meaning of expletive negation, via a diachronic investigation from Latin to French, we establish that expletive negation originates from prohibitive negation. We put forward an analysis of prohibitive negation within Krifka (2014)'s model of embedded speech-act and propose that expletive negation is the continuation of prohibitive negation, and that it is what remains of a long-gone embedded negative imperative in French. Along this line of analysis, the article brings historical evidence in favour of the hypothesis that languages can develop from speech-act embedding to proposition embedding. Our analysis of prohibitive negation as a clause-typing negation marker in Latin and as a verbal mood negation marker brings new evidence to the claim that sentential and verbal mood marking are two intimately related phenomena.
