In proper English usage it's widely recognized to use 'an' in front of any noun which begins with a vowel. Ex. An apple instead of 'a' apple. The converse is true in regard to nouns beginning with a consonant. Ex. A banana versus 'an' banana.
However, my question revolves around nouns whose first letter 'sounds' like a vowel; but isn't. Ex. 'an' hour sounds considerably better than 'a' hour.
Thus, is there an established rule of English utilization saying a person must/should use an article such as 'a' in front of nouns which begin with consonants sounding like vowels?
