This paper deals with the morpho-syntactic properties of Spanish verbs formed by -ear affixation (EAV henceforth). These include deadjectival (e.g. amarillear ‘to go yellow’), denominal (e.g. fanfarronear ‘to behave like a boaster’), and deverbal verbs (e.g. bailotear ‘to dance in an irregular manner’), which do not form a natural semantic class. The purpose of this paper is twofold: first, to develop a unified morpho-syntactic analysis of EAV within Hale and Keyser's (1993) approach to argument structure – as developed in Mateu (2002) and Acedo-Matellán and Mateu (2011, 2013) – and Distributed Morphology; second, to take this proposal as a basis to account for cross-dialectal variation in the productivity of EAV. We group EAV into three basic syntactic classes that share a core structure v+P. We argue that a large subset of unergative verbs must be analyzed as events with a specifier that select for a relational/predicative complement, a type of structure that is shown to underlie verbs with an adverbial argument. -Ear is further checked against unmarked -ar, the default verb-forming suffix in Iberian Spanish. We show that an underspecified analysis of EAV is compatible with cross-dialectal variation in that it accommodates the (non-)predictable range of meanings found across American varieties where -ear has become the default verbalizer.