The paper deals with the inconsistent pattern va a ddormi «go and sleep», which occurs in the Italian dialects and in some literary records reproducing informal speech. According to the canonical explanation it can be traced back to the Latin pattern vade ac dormi, where the coordinating conjunction ac «and» has been preserved. Other residual cases of ac have been singled out in diciassette 'seventeen', tuscan tutt'a ddue «both», neapolitan cumm' a tte «like you». After a scrutiny of the chronology of the records and a detailed analysis of the different patterns, we conclude that the survival of ac in the Romance languages, as is claimed by the supporters of the canonical explanation, is highly improbable. We propose alternatively to consider the pattern va a ddormi just a case of parahypotaxis, that is a mismatch among the different functional (i.e. semantic, syntactic, morphological, pragmatic) components of a sentence, namely a mismatch between the semantic component and the syntactic one.