Theme: Article Plan: Artical types Crosslinguistic variation

a + singular noun beginning with a consonant: a boy; a car; a bike; a zoo; a dog

an + singular noun beginning with a vowel: an elephant; an egg; an apple; an idiot; an orphan

a + singular noun beginning with a consonant sound: a user (sounds like 'yoo-zer,' i.e. begins with a consonant 'y' sound, so 'a' is used); a university; a unicycle

an + nouns starting with silent "h": an hour

a + nouns starting with a pronounced "h": a horse

• 
  In some cases where "h" is pronounced, such as "historical," you can use an. However, a is more commonly used and preferred.
  

A historical event is worth recording.
Remember that these rules also apply when you use acronyms:
Introductory Composition at Purdue (ICaP) handles first-year writing at the University. Therefore, an ICaP memo generally discusses issues concerning English 106 instructors.
Another case where this rule applies is when acronyms or initialisms start with consonant letters but have vowel sounds:
An MSDS (material safety data sheet) was used to record the data. An SPCC plan (Spill Prevention Control and Countermeasures plan) will help us prepare for the worst.
If the noun is modified by an adjective, the choice between a and an depends on the initial sound of the adjective that immediately follows the article:

• 
  a broken egg
  
• 
  an unusual problem
  
• 
  a European country (sounds like 'yer-o-pi-an,' i.e. begins with consonant 'y' sound)
  

Remember, too, that in English, the indefinite articles are used to indicate membership in a group:

• 
  I am a teacher. (I am a member of a large group known as teachers.)
  
• 
  Brian is an Irishman. (Brian is a member of the people known as Irish.)
  
• 
  Seiko is a practicing Buddhist. (Seiko is a member of the group of people known as Buddhists.)
  

DEFINITE ARTICLE: THE

The definite article is used before singular and plural nouns when the noun is specific or particular. The signals that the noun is definite, that it refers to a particular member of a group. For example:
"The dog that bit me ran away." Here, we're talking about a specific dog, the dog that bit me.
"I was happy to see the policeman who saved my cat!" Here, we're talking about a particular policeman. Even if we don't know the policeman's name, it's still a particular policeman because it is the one who saved the cat.
"I saw the elephant at the zoo." Here, we're talking about a specific noun. Probably there is only one elephant at the zoo.

COUNT AND NONCOUNT NOUNS