In English, it is common to contract the words in a sentence. A contraction consists on two words made shorter by placing an apostrophe where letters have been omitted.
Contractions aren't necessary in written English since sing the full version of a word is always grammatically correct.
However, contractions make a piece of writing seem friendly and accessible.
For example Mrs. Bennett claims Mr.bennet has no regard for her Nerves when in reality he claims that he is well aware of her Nerves meaning that he agrees she is crazy