'Where the devil/should he learn our language?' (II, ii, 66—7) wonders Stephano when he finds the terrified Caliban, echoing Ferdinand's first reply to Miranda:

Insignificant as this appears at first, it is new; never before in Shakespeare’s plays have characters called such attention to the fact that they might not speak the same language. Both Mortimer in 1 Henry IV and Henry V marry women of different tongues, but these ladies actually sing or speak on stage in their native languages, and the underscored confusion provides humor and charm. Elsewhere, dramatic license circumvents the difficulty, as Sicilians and Bohemians, Danes and Norwegians, Romans and Egyptians all converse, with our assent, in standard Elizabethan English. The Tempest, though, is different, and these two remarks are only one way in which Shakespeare calls attention to characters speaking. The question of language lies at the thematic center of The Tempest - a play where drops of water ‘swear’, thunder ‘pronounces’, and billows ‘speak’; a play where the controlling pulse derives ultimately from a magician’s arcane book. Shakespeare, in his final romance, returns with uncompromising directness to a problem which concerned him in earlier plays: the inescapable inadequacies of language as a medium for expression and communication. Like its characters, The Tempest demonstrates a heightened sensitivity to words, exploring these inadequacies and searching for a way to make language an acceptable basis for social order.