(No) faltaba/faltaría más

In this paper we examine the functions and origins of the constructions (no) faltaba más and (no) faltaría más through the analysis of the examples extracted from the CDH and CORPES XXI. The different variants are formally and significantly grammaticalized as an interjective sentential idiom of an exclamatory nature. This grammaticalization is manifested by the fixation of the construction and by the loss of the verbal characteristics of faltar. We have confirmed how the change from full syntactic construction to epistemic discourse marker is rendered by the aspect of focalization, and we have differentiated five meanings of the construction. The meaning in the origin of the construction is rejection of something which was previously indicated. The epistemic change from rejection of something which was previously indicated to confirmation of a previous element is caused by the meaning of rejection of something negative, which results in its positive confirmation. The politeness value arises as confirmation of an expression of politeness, leading the construction to adopt this politeness value. Finally, confirmation of posterior elements was indicated from the meanings of confirmation (either positive or negative) of previous elements. This last confirmation is possible because it was frequent in cases of confirmation for the argumentation to continue, so that an argumentative line could be established with both the former and the latter. Finally, we have verified that the construction does not involve any type of covert negation, but instead, its grammaticalization as an interjective sentential idiom of an exclamative nature develops epistemic values intensified by means of exclamation, manifesting surprise, and whose epistemological link has been corroborated throughout the study.