How does Shakespeare use character, language, and themes in Act 5, scene 1, to engage the audience in A Midsummer Night's Dream?
A big question! Here are some points to hopefully get you started.
Act V Scene i commences with Theseus' famous speech about imagination in response to the lovers' stories. A key theme of the play is the relationship between imagination/dreams and reality/reason, and this speech gives you, overtly, the reasons why Theseus favours reason over imagination.
However, it is highly ironic that his disparaging remarks about the poet:
The poet's eye, in a fine frenzy rolling
Doth glance from heaven to earth, from earth to heaven.
And as imaginatinon bodies forth
The forms of things unknown; the Poet's pen
Turns them to shapes, and gives to airy nothing,
A local habitation, and a name.
This is of course what Shakespeare does and does so well in this play.
Moving on to the performance of the mechanicals, despite the hilarious comedy there is a serious message within the story of Pyramus and Thisbe. In Act I Scene i, Hermia and Lysander face oposition to their union and Hermia faces the very real possibility of death if she does not bow to her father's wishes. The recent film version of this play captures this brilliantly with the audience being silent and shocked after Thisbe kills herself, perhaps indicating their awareness of their own fate had not Oberon and Puck stepped in!