From cjvlang.com
From conbinibento.com - タバコ : tabacco, cigarette
The search for katakana words turned up the first image of a sign using おタバコ. Initially, I thought that perhaps it was used for emphasis, since it was a public sign, but that didn't really answer why that same word is listed in hiragana with Minna no Nihongo. Aren't you supposed to write it in a specific way? I remembered that there was a series of "Smoking Safety" signs in Japan, so I looked up what they used to write tobacco with...hiragana. Now I'm confused. When we asked Hamada sensei why it was written in different ways, he emphasized that you are capable of writing katakana words in hiragana, and that it is basically up to you. So although I got the idea that tobacco was common enough to write in hiragana, there are no rules dictating that it must be written in a certain way. I suppose this particular katakana use would be categorized as a loanword (falling in/out of favor as foreign), emphasis, and asserting that the katakana/hiragana "rules" are not as rigid as I thought.
From subway.co.jp- アボカド : avocado
- プリクラ : purikura
Each textbook has different katakana explanations because it is so flexible and open to interpretation. They all seem to agree that it is used for foreign and loan words, but they seen to also focus on different aspects of the language. Yookoso and Japanese for Busy People directly mention katakana can be used for emphasis and onomatopoeia, so they provide an understanding of katakana in a greater context of contemporary uses in writing and television. The accepted katakana explanation is ultimately a matter of author preference.
