Phonics Facts: Articles (adjectives) A, An, and The

When the word begins with a vowel sound (a,e,i,o,u) then you should use ‘an.’ 

Example: an apple, an umbrella

When the word begins with a consonant you should use ‘a’. 

EXCEPTIONS
However with this rule there are exceptions. If you are using a word with a silent ‘h’ (honest), then you have to use ‘an’.  

Example: an honest student

Another exception:  the vowel U. When ‘u’ makes the same sound as the ‘y’ in “you”, or ‘o’ makes the same sound as ‘w’ in “won” then you should use ‘a’. 

Example: a one-legged dog     a unicorn