愛人 ('a lover mostly on affair' in Japanese ⇔ 'wife' in Chinese)
Wrong: In China, it doesn't mean a thing [remember, the Chinese in China DO NOT use the Traditional Chinese script, which is what 愛 is written in: In Simplified Chinese script = 爱]. And 爱人 is ONLY used in China. And it doesn't mean "wife". It means "either one of the spouses" or "both spouses"[Chinese doesn't use inflections as a grammatical rule]: If the speaker is a woman, then 爱人 refers to a husband. If a man says it, then 爱人 refers to a wife.
In other parts of the world, "wife" = 太太 or 老婆, but NEVER 愛人 and 老婆, laopo is borrowed from Hong Kong into China. But Hong Kong uses Cantonese & English, while China uses only Putonghua.
手紙 is NEVER used in China. only in Japan. and like the above, in Chinese people use Simplified Chinese which 紙 isn't. 紙 = 纸 in Simplified Chinese = paper. 手纸 is Chinese slang, not official term for "toilet paper". If you want the official term, then use "卫生纸" or 衛生紙 in Traditional Chinese.
"Chinese characters are also known as sinographs, and the Chinese writing system as sinography."
BULLSHIT: Don't EVEN use Latin word SINO to refer to Chinese! It's not accurate: Latin didn't have a word for "Chinese" so they borrowed from Hebrew or Arabic, so it's not even original!!! No such thing as "Sinograph" or "Sinography"!!! No matter what, that's not a developed word and doesn't relate to the Chinese language whatsoever.
The only word which you don't have in English is called "Sinosphere", which with a lack of words must be used in order for others to understand. I would prefer to use the Greek word Kinezo- or Kineziko- but that's due to borrowing from German for the name of China = Kina.