English alphabet
The apostrophe, while not considered part of the English alphabet, is used to contract, or shorten, English phrases. A few pairs of words, such as its (belonging to it) and it's (it is or it has), were (plural of was) and we're (we are), and shed (to get rid of) and she'd (she would or she had) are distinguished in writing only by having or not having an apostrophe. The apostrophe also distinguishes the possessive endings -'s and -s' from the common plural ending -s, a practice that began in the 18th century; before, all three endings were written -s, which could lead to confusion (as in, the Apostles words).