Why do TV people say *an* historic event?

Question

It's been 30+ years since grade school, but I was taught that if the "H" is heard (hah sound) - then use "a" before it (e.g. a history book). If the "H" is silent, as in hour, use the "an" before it (e.g. an hour). Why are TV people still saying Obama's nomination is "an" historic event? Shouldn't it be "a" historic event?

Answer 1

http://grammartips.homestead.com/histori...

Answer 2

According to English pronunciation rules (Did I just say 'rules'?!), we use 'a' before a word beginning with a consonant sound and 'an' before a word beginning with a vowel sound. As the word 'historic' begins with the consonant sound /h/, then we should use 'a' and say 'a historic'. Well, this is what we all know.

However, many people prefer to use 'an' before words that start with /h/ and that have three or more syllables, so this is also accepted as valid. 'Horse' only has one syllable, so it just follows the general rule ('a horse').

Another example is 'an hypothesis'. It's just the same case as 'an historic'. Consider that the /h/ sound is so weak that sometimes people don't even pronounce it, as in 'what' and 'where'.

So both ways are correct, though 'a historic' is better.