In Vowels^x, Determiners^x, Nouns^x

The rule with a and an is that you use a when the word that follows it starts with a consonant sound, and you use an when the word that follows it starts with a vowel sound. You probably knew that given you used an correctly in your sentence, but I thought I'd mention that for others who may...

1. He eats an apple. 2. He eats another apple. 3. He eats an another apple. I know the third sentence is flawed. However, the words starts with a vowel needs the determiner 'an'. To say ' He eats a apple' is incorrect. The word 'apple' is already defined by the determiner...