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Why do we use an before old lady and a before a one eyed giant?

marked as duplicate by Dan Bron, jimm101, tchrist Feb 27 '18 at 12:42

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  • It is a question of pronounciation rather than orthography. - one" and "unit" for instance, begin with vowels, but the initial sounds are those of the consonants "w" and "y" as in "won" and "you" therefore you say : a unit or a one time thing, etc. – user240918 Feb 27 '18 at 11:49

It has to do with pronunciation. The word “one” is pronounced such that it seems to start with a “w”. Another common example is “a unicorn”, where “unicorn” is pronounced as if there is a “y” in front. The phrase “an hour”, on the other hand, sounds like “our”, which is a vowel. Hence it is “an”.

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