Fun fact: Japanese even has a word for foreign characters, "gaiji", and it's extremely common in Japanese ePUBs to use small square images very frequently for characters not in the current font, using the term "gaiji" in the CSS class names used for these characters. And at least one mainstream ePUB reader has special code to detect these gaiji and adjust its rendering to make them behave better.
Similarly, the word "loanword" (used to describe words borrowed from other languages) is gairaigo 外来語 which is literally 外来 (gairai) "foreign" + 語 (go) "word/language". Japanese is filled with words where you can often figure out the meaning purely from the characters used!
