Using Articles A and AN

English for Today by Ganiu Abisoye Bamgbose (Dr GAB)

Using Articles A and AN

Article “a” is used before consonant sounds (not necessarily letters).
A boy, a union, a university.
You’ll observe that u is a vowel letter but it generates the consonant sound /j/ as found in yam.

Article an is used before vowel letters (not necessarily vowel letters). An umbrella, an SSS 2 boy. Note that the consonant sound s generates the /e/ sound in the expression an SSS 2 boy.
GAB