This dissertation aims to explain, from a microsyntactic point of view, variation and linguistic change in use and values of minimizers in negative contexts (we understand minimizers as 'nouns that denote a minimal amount or a part of something'). We assume that synchronic variation is the reflection and the product of diachronic linguistic change. We approach the reanalysis of negative minimizers by comparing, cross-linguistically, the features associated to these lexical items in unexplored Romance varieties of the Pyrenees. We show that the reanalysis of negative minimizers is conditioned by a complex interplay of factors that affect all levels of grammar. Nevertheless, there are systemic tendencies and patterns underlying the process of reanalysis, also regulated by the principles of economy and computational eficiency. In Chapter 2, we introduce the fundamentals to explain variation and linguistic change regarding the negative expressions in Romance varieties. We analyse the factors that determine polar sensitivity of lexical items, as well as the semantic and syntactic dependencies necessary to check the features assigned to different expressions of negative polarity. The concepts presented in this chapter constitute the backbone of our approach to the process of reanalysis of minimizers, from their nominal use to the functional values. In Chapter 3, we look into the reanalysis of nominal minimizers as Negative Polarity Items (NPIs) with quantificational features (labelled the Incipient Jespersen's Cycle). We establish the semantic and syntactic dependencies, the licensing conditions and the structural configurations determined by different features characteristic for each of the negative minimizers at this stage. We also explore the consequences of featural specifications in contemporary and diachronic negative concord relations in the varieties under study. Chapter 4 is a revision of the broad terms of emphasis and reinforcement in relation to the use of minimizers as NPIs. The fact whether quantificational features are attributed or not to emphatic NPIs is considered to be determining in the distinction between intensive and presuppositional markers within the broad class of emphatic markers. We analyse the structural configurations that explain the reanalysis of intensive markers as presuppositional, dispossessed of quantificational features and restricted by information-structure factors in their use. In Chapter 5 we present a formal account for the cycle of renewal of expressions of negation (i. e. Jespersen's Cycle). We argue that the use of minimizers as presuppositional markers, together with other factors studied, constitutes a stage necessary for minimizers to become markers of negation. Our contemporary and diachronic data allow us to shed light on the featural characterisation of minimizers as negative markers and to present an overview of tendencies and patterns at every stage of the process of reanalysis of negative minimizers.