I started out learning hiragana and katakana first. it's like a kid learning how to write letters in print and studying the alphabet, then learning to write in cursive. Hiragana is the first thing to start with. When you've learned it by heart, move on with Katakana and basic kanji. As far as speaking and understanding the language, go to the lessons on here. They show you sentence structure, simple words, and very necessary do's and don'ts. Also, the flashcard trainer is very helpful and effective! Take your time to learn, or nothing will stick. :)

I'm sorry my answer was hard to understand. Stated simply, most words use じ and ず, and you simply have to memorize the small number of words which use ぢ and づ in their spellings.

In modern Japanese じ and ぢ sound virtually alike, and ず and づ sound virtually alike. However, you cannot interchange them in word spellings, just as you cannot interchange おう and おお.

I hope that is more clear.

There are no easy rules you can learn. These pairs of sounds (じ and ぢ, ず and づ) are said to have been farther apart in Japanese as it was spoken long ago.

じ and ず occur much more frequently than ぢ and づ.

One pattern is that ぢ and づ often appear in words right next to a ち or つ: for example, 続く = tsuzuku = continue is spelled つづく in kana; 縮む = chijimu = shrink is spelled ちぢむ in kana.

wow thanks a lot tonyさん.

appreciate your help and your interesting explanations ^.^!

Thanks tony san :D very clear explanation out there. Sorry but i forgot to ask, how do we type を? It always shows　お when i type "o".

You can type them as di and du, respectively. This is kunreisiki (kunreishiki) Romanization, in which chi = ti and tsu = tu.

The more usual Romanization represents both じ and ぢ as ji, and both ず and づ as zu, which is why there is no natural way to type di and du in that Romanization style.

:)