Énfasis y orden de palabras en algunas construcciones con vaya

The Spanish subjunctive form vaya historically split into different form and has given rise to units of different categories which show different syntactic behavior, from the interjection (iVaya!) to more or less fixed expressions in which the original movement meaning of the verb ir has bleached into those of doubt or desire (Deja que se vaya > Vaya con Dios, Vaya por Dios, Vaya usted a saber...). Alongside these forms, there are other sequences whose grammatical boundary with the interjections has not always been clearly delineated: iVaya mierda de nudos!; Vaya susto que me has dado...; Lo dicen y vaya si es verdad. Are we then dealing with an interjection combined with an adjacent unit or, on the other hand, are vaya or vaya si acting as intensifiers of the syntagmatic group to which they belong? We here defend the latter hypothesis with a special focus on those cases in which vaya, is morpohologically frozen and appears to act as an intensifier of a predicate or, in different contexts, a noun. Using a Functional Grammar approach, we examine the grammatical properties of constructions such as Vaya si es verdad; Aquellos no lo sabian y estos vaya que lo saben demand (in particular, suprasegmental features and word order), their syntactic variants and their similarities with other emphatic constructions involving stressed relatives or quantifiers.