So I’ve had this problem for a while, but I’m posting it here for posterities sake.
I found out about the “++” special phoneme a while ago, and i thought to test it in a variety of conditions. It generally works with 3+ notes: on the note with “++” the word linked to the note is completed. But weird things happen with 2 notes, namely this:
all the phonemes have shifted to the second note, leaving the first note as a silence. I find this behavior odd, and not really intuitive, so I’d just want an official “yes, this is how it’s supposed to work.” or “no, that’s a bug.”
3 notes version, which works as I expected:
Addtional note: Did some experimenting, and found that ++ shifts all the syllables it voices to the last instance of it, so for example:
konpyutaa / + / ++ / ++
outputs:
ko / n / SIL / pyutaa
Is this also expected?
tl;dr:
For an input: kohii / ++,
I expected ko / hii but I got: SIL / kohii
++ is intended to be used in conjunction with - or + in order to complete a word when multiple phonemes are remaining.
You can accomplish this with kohaimaru- / ++
In your example where you expect ko / hii this makes no sense. That’s the purpose of +, not ++. The correct input would be kohii / +. Technically you could also do kohii- / ++, but there is no reason to do that and while it accomplishes the same result I would consider it bad practice.
One correction on my part, while the kohii example doesn’t change the phoneme timing, I neglected to select an actual voice for my screenshots. The dynamics do change slightly to reflect the long イー rather than simply holding the same phoneme longer.