Satire is a form of writing where the goal is to make fun of or ridicule the society by pointing out problems and vices and how they are incorporated in the way of living of the period of time that is ridiculed. It is used as a form of social criticism and is often pointed towards government policies or individuals.
Irony is writing tool that is used also to make fun of things by having the spoken words be different from what is actually happening. It is presumed that the audience is aware of the true state of things so that they can understand that what is being spoken is actually not the truth and therefore it creates a comic effect.
Sarcasm is often mistaken for irony because they often overlap, but on its own it's not always ironic. It's usually formed with sharp and bitter remarks towards something with the intent to offend or ridicule them and point out what a problem within the society might be.
She employs all three very effectively in order to ridicule the social conveniences of the time. Her female characters are often highly sarcastic women who don't fit the current status quo of the highly conservative traditional society. The satire of sense and sensibility is in the fact that the social problems of such a society are criticized with a desire for a more progressive change and gender liberation. Irony is often employed with her male characters who are supposedly rich noble land owners but in reality are completely useless members of the society but present themselves as the high class or as nobility.
