[numpad0]

You can't mix encodings in a single file. A file has one encoding only. It was not possible before Unicode to mix two languages in a single file, whether the languages involved were Chinese or Japanese or French(English was an exception).

Now, if a file was encoded in Unicode, and/or if it was in such document format that support inline font specification, such as HTML, then you could mix two languages without having to stick to one language by e.g. wrapping <font face=Helvetica>paragraphs and words</font> <font face=Futura>with tags</font>.

My point is, it seems that the author is not aware that each of CJK languages are only understood within each countries, in both writings and speeches, and that's somewhat peculiar.

[ablob]

You may not be able to mix encodings, but mixing languages has always been possible. If you used a French encoding you would be able to write in English, but not the other way around. I'd wager there are similar cases for cyrillic text. What Unicode gave us is its universality (heh). You don't have to carefully select an encoding able to represent the languages you wish to use anymore.