日本語 Japanese Ask Questions Thread 6

If you have a question about the language, ask it and fellow 4channers might see it and answer it for you.

Japanese - Ask questions thread
http://dis.4chan.org/read/lang/1174719097/1-40

日語 Japanese Ask Questions Thread2 質問
http://dis.4chan.org/read/lang/1206158123/1-40

日本語 Japanese Ask Questions Thread 3
http://dis.4chan.org/read/lang/1267485093/1-40

日本語 Japanese Ask Questions Thread 4
http://dis.4chan.org/read/lang/1302350850/1-40

日本語 Japanese Ask Questions Thread 5
http://dis.4chan.org/read/lang/1330050873/1-40

I'd like to ask what is probably going to seem like a very stupid question.  Nearly everyone (that I've seen, anyway) advocates learning Japanese by learning to write Kana and Kanji from the get-go.  I understand the necessity of learning to write and read in Japanese, but why is it a bad idea to start learning basic speaking vocabulary and grammar first, the way you learn a language normally?  I'm not trying to take the easy wait out or anything, I just don't understand why it's not better to learn to speak the language some first, and then learn to write it, like you would if you were a child.