Verb processing is broadly described as being problematic in agrammatic aphasia, a medical consequence of left frontal hemisphere damage. Errors in verb processing are also observed in children with Specific Language Impairment, a developmental language learning disability. The aim of the present study, entitled “Cross-linguistic and Cross-population Verb Processing” is to collect and compare verb processing disorders in acquired (agrammatic) vs developmental (SLI) language disorders in order to determine whether they are of the same nature and to define the underlying reason for their similar symptomatologies. The data will be collected and analysed with a cross-linguistic perspective: in Basque, a language isolate which has rarely been studied in the context of language pathology, and French and Spanish, two romance languages that are part of the Indo-European family whose grammatical properties contrast with Basque (e.g. Basque is an ergative language, pro-drop with pluripersonal verb agreement, whereas French and Spanish are accusative languages with subject-verb agreement using subject and object clitics). This study will have an experimental and inductive approach by creating theoretically and linguistically based language tasks aimed at exploring the cognitive substrate of verb processing. Also, neuroimaging (event related potentials or ERPs) and eye-tracking methods will be developed to complement traditional elicitation and pen and paper tasks. In sum, the goal of this study is to contribute to research on the neurocognitive underpinnings of human language, with a specific focus on verb inflectional processing, while using the grammatical properties of Basque and their contrast with French and Spanish. The study of impaired vs normal verb processing in three languages with distinct morphological properties is particularly interesting for the exploration of neuropsychological bases of human grammar in general, and for morphological processing in particular.