うto double o?

[Arcticfox320]

I was at http://www.coscom.co.jp/ in the Kana Workbook they have(http://www.coscom.co.jp/cybtext/kana/hi ... index.html), and down at drill 4, う being placed after an o turned it into an o. Is this right? What are the rules for this? I'm kinda new at Japanese, so sorry if I'm missing something obvious = \

[CviCvraeVtMoriar]

A prolonged o is written thusly:

おう
こう
そう
とう
のう
ほう
もう
よう
ろう

ごう
ぞう
どう
ぼう
ぽう


This is different. This is two consecutive o's pronounced separately:

おお (as in 大きい - pronounced おおきい, not おうきい)
こお
そお
とお
のお
ほお
もお
よお
ろお

ごお
ぞお
どお
ぼお
ぽお


Prolonged a sound:

ああ
かあ
etc...

Prolonged i sound:

(Technically, two consecutive i sounds are to be pronounced slightly separately but most people just make a long i sound... lazy people.)

いい
きい
etc...

Prolonged u sound:

うう
くう
etc...

A prolonged e sound is more commonly written えい, but is sometimes ええ

えい
けい
せい
etc...

ええ
けえ
せえ
etc...



These rules, however, are not true of writing in Katakana.

E.G.:

アー
イー
ウー
エー
オー

カー
キー
クー
ケー
コー

サー
シー
スー
セー
メ[

etc...

[CviCvraeVtMoriar]

So, if you want to make a long ko sound, you write こう not こお.

こ = ko
こう = koo
こお = ko-oh (Though, lazy people often pronounce this in a fashion very similar to that in which they pronounce the forgoing... I fall into that category, incidentally.)

[Arcticfox320]

Ah, I see now, thanks