This paper argues that it is the causative structuration of the motion situation that seems to be the crucial factor determining the status of intransitive verbs of locomotion and their potential to enter into a certain set of syntactical configurations. More specifically, the paper attempts to provide arguments against the commonly held view that locomotion verbs in directed motion constructions are unaccusative (this applies to both intransitive structures and transitive causative structures). If the subject argument of an intransitive manner of locomotion verb displays reduced agentivity (i.e. if it displays properties of both an agent and a patient), it is not admitted into transitive causative structures, in spite of the alleged unaccusativity of verbs that are admitted into them. The inability of path verbs to causativize is explained by appealing to the fact that these types of verbs render motion as not forming part of an energetic (i.e. a causal) chain. Related to this is the fact that the subject argument of these verbs falls outside the agent vs. patient classifi cation, which is commonly claimed to be directly related to the verb’s unergative vs. the unaccusative status, respectively.

This paper first looks into mechanisms that license the formation of transitive causative constructions with the motion verbs run and walk. As a further step, it takes into consideration intransitive constructions with these verbs and, in doing so, it contrasts the meaning of run with walk as its most natural counterpart. The paper provides evidence in favour of positing one of the verb’s senses as core, representing a kind of starting point against which some of the other motion senses are established. In this way, arguments are offered in favour of the lexical network model of polysemy. At the same time, it is shown that the extensive usability of run (and, by the same token, the restricted usability of walk) is closely related to the degree of the verb’s context-sensitivity, which, in its turn, points to the conception of the verb’s meaning as representing a dynamic potential.