What is katakana?

Answer 1

Katakana is the youngest of the three Japanese set of alphabetic characters, or better said syllabary. 片仮名 /ka ta ka na/ as the writing suggests, it means 'one of the two kana' or 'fragmentary kana'. (kana is the term referred to hiragana and katakana together.)

As to why they are called syllabary rather than alphabet, it is because they each do not represent a single sound like 'm', 't' or 'ch' alone, but the combination of those consonants with each of the five vowels (a, i, u, e, o).

Since katakana was taken from kanji, its characters have a more angular shape, in contrast to hiragana which are curvy and thus more flexible for calligraphic writing. Some characters are similar to their counterparts in hiragana. Examples: (the group 'k')

ka - ki - ku - ke - ko

か - き - く - け - こ : Hiragana

カ - キ - ク - ケ - コ : Katakana

Katakana is basically created to write non-Japanese words such as loanwords, names or titles of places and people etc in Japanese. But in actual usage it's also common for it to be used instead of hiragana or even kanji, since it has a stylish sense to it. Sometimes, even if slightly, its eye-catching shape provides emphasis and/or signifies a specific meaning of a word, as for homonyms (words with the same reading, but different meanings and mostly different spellings too) are quite usual in Japanese.

Simplest of words, names of animals, even Japanese names and so on, which originally should be written in kanji, can be found written in katakana, yet that does not imply that just anything can.

Katakana has the same 'main characters' (monographs) as hiragana, but as for derivations made by combining two main characters (digraphs), katakana has by far the upper hand. Syllables like 'fa', 'fe', 'vo', 'di' etc which originally don't exist in Japanese phonology are only existent to katakana, through which different foreign words can be scripted in Japanese.