When do we use Kanji? Hiragana? And what about Katagana?
Kanji are used for
content words like:
- nouns (e.g. sea 海 or hero 英雄)
- stems of verbs, that means the part of the verb which does not change (consider the English sentences "he walks" and "he walked." walk- would be the stem and -s & -ed the (inflectional) endings).
挑みました = idomimashita (past form of the verb idomu) = (he) challenged
idom- = stem of the verb
-imashita = ending of the verb which can be changed in numerous ways (for
example to express past meaning)
- stems of adjectives, that means the part of the adjective that does not change (consider English adjectives like "faster", "higher": fast- and high- would be the stems and -er the (inflectional) ending)
白い = shiroi (white)
When do we use Hiragana?
Hiragana is used for grammar, that means it's used for:
- the inflectional endings of verbs, the part that can be changed for all kinds of grammatical purposes, for example to express past meaning (挑みました = idomimashita)
- the inflectional endings of adjectives, the part that can be changed for grammatical purposes (白い = shiroi)
- grammatical particles: small words that describe grammatical relationships between words or parts of a sentence (like "with", "of", "for", "to", "from", "before", "after" etc.):
は, の, を, に, で, が
- smaller words, often function words like それで ("and", "because of that")
Veeeeeery generally speaking, Kanji are used for content and Hiragana mostly for grammar.
About Katagana
For every Hiragana character there is a matching Katagana character. For example, the matching Katagana for the Hiragana character の is ノ . Both characters -- Hiragana の and Katagana ノ -- represent the syllable no. However, Katagana characters are only used to transcribe words of foreign origin, like
foreign names, e.g. Tiamat ( チアマト) from our example sentence or Mary (マリー)
and loan words, e.g. PC (ピーシー).
As you can see, Katagana characters look less rounded than Hiragana.