Because you never know who’s reading your mail
Apropos past posts on intelligence, I just came across a Japanese website that has an English page on the codes and ciphers used by the English during the Spanish Succession.
Presumably the webmaster has an interest in historical cryptography (why not? why not indeed). With the exception of a few dozen pages on various early modern ciphers and codes (including American Revolutionary), the rest of the site seems to be in Japanese. Apparently ciphers are a subject best discussed in English.
For the hell of it, I include my own small contribution: