The English language allows for contraction in some words, that is, their shortening. A word having an apostrophe (‘) is one of the ways to know that it has been shortened, although an apostrophe is also used for other functions.
Here are some lists of words you can have in their short forms:
Contraction can occur between a noun, pronoun, and verb, as you can see in the examples above. They can also be negative.
The list above isn’t exclusive, and it shouldn’t be taken to mean all English contraction words. Nevertheless, with this, you can improve your vocabulary.