The pronunciation of 'Hawaii'

It seems to me that it might be the same small group of Midwesterners—my grandmother, from Illinois, was one of them—who say Missoura, Miama, Cincinatta. I don't know what the rule is for which place names to do this with. They are perfectly capable of pronouncing an /i/ at the end of a word ... they say happy rather than happa.

I was also under the impression that there are very few people who do this with any word other than Missoura nowadays, but I don't live near the part of the Midwest this pronunciation is from, so I could be wrong about that.

Added: In fact, Googling seems to confirm this; e.g. see this book.

This pronunciation definitely exists in Missouri (called Missoura by a large fraction of its inhabitants), but from looking through the few results for "Hawaya" on Google, it seems that some people from Illinois and Ohio also use it.

I think that it is less of a regional difference than an age difference. As several others have pointed out, they hear older people pronouncing it 'Hawaya'. While I can't speak for the other words people have mentioned, the native pronunciation of Hawaii is quite unusual for English speakers. First is the ai diphthong, followed by a glottal stop (a sound not really used in the middle of English words too much, an exception is 'uh-oh'), with a word final e sound that doesn't have a real solid consonant sound before it. The difficulty for English mouths means that when the word was first encountered, people would morph it to fit what they could comfortably say, and only once we became used to the peculiarities of the word did people start to say it more like the native pronunciation.

Recently I was listening to a podcast that mentioned this specific pronunciation, around the 15 minute mark at 14:05 is when the discussion of Hawaii begins (warning - profanity in the beginning of the podcast, as it also discusses the use of profanity in old cartoons.) The podcast can be found here