Puns, which are words that can have more than one meaning in the context in which they are spoken (they are also referred to as "double entendres," or words with a double meaning), abound in this madcap, comic play. One example is as follows:

In act 2, scene three of Twelfth Night, Maria puns on the words "ass" and "as" in line 154. When Maria repeats the Andrew's last word, ass, she both calls him an ass and makes the statement: "Ass [as] I doubt not."

Malapropisms also abound in this play. Malapropisms occur when a character uses the wrong word—but a word that sounds close to the right word. This makes the speaker look ridiculous and the audience laugh. One example occurs in act I, scene three, when Sir Toby Belch talks about "scoundrels and subtractors." Subtractors is the malapropism; what Sir Toby means to say is detractors.

Here is an example of a pun from Act I, Scene 5 of the play.  Maria and Feste, the fool, are talking to each other.  They say:

• Maria. You are resolute, then?

• Feste. Not so, neither; but I am resolved on two points.

• Maria. That if one break, the other will hold; or, if both 315
  break, your gaskins fall.

The pun here is on the word "points."  Feste is using it to mean a point like some idea that he has decided on.  But Maria is using it to refer to the points of his suspenders -- the place where they are attached to the buttons on his pants.

You can find a malapropism in Act I, Scene 3.  In this case, it is Sir Toby Belch talking.  He says

By this hand, they are scoundrels and subtractors
that say so of him. Who are they?

The malapropism is "subtractors," which ought to be "detractors."