TO enjoyor merely endureItalian opera, especially Verdi, a word-for-word acquaintance with the libretto is not essential. Most listeners will be able to navigate the critical junctures of the average plot by developing a familiarity with a handful of catch phrases. Such verbal adornments keep the melodrama moving and can be used to tell almost any story. As in the following dialogue drawn entirely from Verdi's Ernani which took place between an opera-loving wife and a bored husband on opening night at the Met. SCENE 1
He: Beviam! (Let's get a drink!)
She: Per pietà. (Wait until intermission, dummy.)
He: Io sono il re!...