While many of the カタカナ expressions were in fact loan words, onomatopoeia, and animal words. I found that before World War II, many official documentation was in カタカナ instead of hiragana. Many of these expressions, especially in the military, were original Japanese words. I researched further, and found out that especially in documentation and in the military, カタカナ was the dominant writing system. This was especially true for men, as hiragana was seen as a "girly" way to write. Women were less likely to be encouraged to learn katakana, and the artistic style of hiragana was used more for literature and poetry. じゃ、 また Molka です。