For one thing, in Midsummer Night's Dream there are the language styles of poetry, which is spoken by central characters like Hermia and Theseus and Puck and Titania, and prose spoken by characters like Bottom and Quince. Shakespeare traditionally uses the the elevated style and diction of poetry for elevated characters while using the ordinary style and diction of prose for lesser characters:
You can play no part but Pyramus; for Pyramus is a
sweet-faced man; a proper man, as one shall see in a
summer's day; a most lovely gentleman-like man:
therefore you must needs play Pyramus.
In addition, Titania uses poetic language from the pastoral tradition, speaking of pastoral elements that laud nature and describe nature with admiring detail. As an example, she speaks of "rushy brook" and "whistling wind," both characteristic of descriptions in the pastoral tradition:
TITANIA: Met we on hill, in dale, forest or mead,
By paved fountain or by rushy brook,
Or in the beached margent of the sea,
To dance our ringlets to the whistling wind,
It might also be said that the word play Shakespeare uses is another variety of language style in the play. Demetrius and Helena offer a good illustration of word play and punning on the word "sick" and the idea of being made sick by someone: Demetrius says he is made sick when he has to look at Helena, while Helena turns the word around and says she is sick when she is unable to look at him:
DEMETRIUS: Tempt not too much the hatred of my spirit;
For I am sick when I do look on thee.
HELENA: And I am sick when I look not on you.