The Japanese language has three kinds of characters; hiragana, katakana and kanji.  The Chinese character, kanji, was brought from China.  It is thought to have been introduced around the third or fourth century, although this has not been proved.  Kanji, which is an ideogram character  (to represent meanings), started to be used as a phonogram (to represent sounds) called Manyo-kana.  As kanji became more widely used, it was simplified.  This simplified form became hiragana.  Hiragana has a roundish shape as shown below, and it was considered to be the letters for private use and female use.  

ex.   安→ あ 以→ い  加→ か

Japanese word order and Chinese word order are different.  Small size kanji (kun’ten) were placed next to kanji to indicate the Japanese word order when reading classical Chinese.  Then it was simplified and became katakana.  Many katakana were made from a part of kanji as seen below.  Katakana has rather straight lines.  

ex. 阿 → ア 伊 → イ  加 → カ

The three kinds of characters are used in different ways.  Normally katakana is used for loanwords and foreign names like koohii (coffee) or nyuuyooku (New York).  Most content words are written using kanji.  Functional words like desu (to be), particles, and some Japanese origin words like oishii (tasty) are written in hiragana.  All three characters can be used in one sentence like below.

ex.    彼         は           ミラ  ー     さ ん     で す.

       kanji    hiragana  katakana   Hiragana

       He   topic maker  Miller      Mr.          is

        He is Mr. Miller.

Japanese period and comma:  

The Japanese language uses a maru (circle) at the end of sentences and ten (dot) for semantic separation in a sentence.  Traditionally Japanese does not use the question mark “?” for an interrogative sentence.  Unlike English there is no space between words.  Instead a combination of the three kinds of characters can indicate if it is a meaning word, a foreign word, or a functional word. 

明日の朝,                    トムさんに会います。

Tomorrow morning   Tom  Mr. with meet 

“Tomorrow morning, (I) will meet Tom.”