[Edwin]

The Japanese hyphen isn't a hyphen!

I see a lot of confusion about this, it's basically a way to transform certain letters into other letters, a bit like an accent in French.

So "ア" is a short "ah" and "アー" is a long "ah" and both have their rightful place in the language. It's true that there are SOME cases where either could arguably be used, because the word being transliterated from a foreign language sounds like it could go either way, but MOST of the time there is a single correct form.

For example, ホームページ means "homepage" but ホムペジ is just garbage (at best, a pretty horrible typo).