The play consists of two plots: the separation and ‘adventures’ of Viola and Sebastian, and the gulling of Malvolio. These create their own ripples – for example, Olivia and Orsino both falling for Viola/Cesario, which lead to further complications and revelations.

The play contains many of the conventions of Shakespearean comedy and drama: confusions caused by twins or mistaken identity, farcical behaviour, comic archetypes and the marriage resolution.

Language is shown to be unstable and unreliable: people say things others cannot understand; words (such as the letter to Malvolio) mislead and are misinterpreted; language conceals and reveals, in equal measure.

Shakespeare’s comedies and the later romances often feature music and songs. As well as adding diversion for the audience, they comment directly, or ironically, on the action.

Much of the imagery in 'Twelfth Night' is surprisingly dark. For example, descriptions of love being like a sickness or infection occur frequently.