This document discusses the different types of articles in English grammar - definite and indefinite articles. It provides examples of how indefinite articles (a/an) are used depending on whether the following word begins with a vowel or consonant sound. The uses of indefinite articles include specifying grammatical definiteness of nouns, indicating a singular countable noun representing a class, making a common noun out of a proper noun, and referring to professions. Definite articles (the) are also mentioned as a type of article in English.