GRAMMAR GIRL

. . . a giraffe, an elephant

• Articles can be confusing. A, an, and the are articles.
• An article is an adjective that modifies a noun.
• The is a definite article; a, an are indefinite articles.

Use the to refer to specific nouns. Remember, it's a definite article.
I ran the marathon  [refers to a specific marathon].
I ran a marathon [refers to any marathon.].

Indefinite adjectives a, an refer to any member of a group.
My son wants a car for Christmas. {What car? We don't know yet.]
I saw an emu at the zoo. [Many emus live at the zoo. Which one did you see?]

Observe the sound that begins the noun.
Use a before a singular noun beginning with a consonant: a truck, a girl, a doctor
Use an before a singular noun beginning with a vowel (a,e,i,o,u): an igloo, an average, an opera

•  Y is weird: it is a consonant when it comes at the beginning of a word [yuh sound as in yummy],
• a vowel when it comes anywhere else but the beginning of a word [sandy. . ..long e; dye  . . . long i;  gym . . . short i
• a vowel suffix: ice/icy; flash/flashy; skin/skinny.
• THEN, if y ends a word: baby/babies

An historical event [ h is pronounced]; however, a historical event has become acceptable.
Check out NOUNS on SCHOOLHOUSE ROCK. http://www.youtube.com/watch?v=E2iLAI0gUW0