For the case of a prolonged sound mark after a Latin letter, I don't know
how to classify this usage, but my translator persisted to say it was
correct, and refused to insert a space before it (and he was probably
right if it's effectively interpreted as an extender of the last vowel, even
if it's a latin vowel...
Not everyone knows well about characterset/charactercode. So it is very often that a native speaker makes a mistake of this kind.
Well, U+30FC (KATAKANA-HIRAGANA PROLONGED SOUND MARK, Shift_JIS 213C) *should* be used only after a hiragana-katakana letter. As to separator(?), we *should* use two consecutive U+2014 (EM DASH, Shift_JIS 213D).
However some people use a single U+2014 as PROLONGED SOUND MARK often unknowingly but sometimes knowingly preferring the character shape of U+2014 to that of U+30FC.
The use of U+30FC instead of two U+2014 is simply wrong. Many Japanese people are affected by this mistake presumably because they would not know U+2014 (Shift_JIS 213D) is different from U+30FC (Shift_JIS 213C) and/or U+30FC would be easier to enter than U+2014 via Japanese Input method. However you would not need to correct your translator. Japanese publishers seem to be well aware of common mistakes of this kind ;-)
Kino
