This paper focuses on the Basque adverbial suffix -ka when it suffixes to verbal periphrasis. The suffix, whose principal meaning is ‘‘in a repeated way'', is present in all the Basque dialects but it appears more often in the North Pyrenean ones. In this context, it shows a strong preferance towards both intransitive and imperfective constructions. Basque is a dialectal variation language in which the grammatical category of the verb causes more dispersion than the other categories. The adverbial suffix -ka helps us to say more: a certain category of intransitive verbs causes more dialectal dispersion than the others. The adverbial is less the cause of such a phenomenon than a symptom showing where it develops.