you mean using a Japanese VCV and trying make them sing English?
I do that a lot actually!!! lemme see if I can help
first about your main question; splitting up words. i'm guessing you mean you're not sure how to split each syllable up to make an english word? since each VCV note is one syllable, i usually just sound it out. If I wanted to say "window", I'd first sound out the syllables "win" "dow", and then picture how it'd be said in VCV. "ui _ i nn _ n do" would be the literal english -> VCV translation. But for me personally, i'd have it said like "ue _ e nn _ n do _ u" because "weendoh" sounds disgusting and I'd much more prefer it said "wendow"
it's hard to explain without screenshots so lets try this lol
here i made a Japanese VCV UTAU sing the phrase "In the summer time" in English (engrish actuarry :P). the entire string of syllables are actually "i zu _ e nn _ n va _ a sa _ a me _ e a _ a ta _ a i _ i mu"
when making a Japanese VCV bank sing English you'll find that a lot of banks are missing common English sounds like "th" and "er" etc etc... so we gotta improvise sometimes :/
for the word "the" since the UTAU I was using didn't have the "th" sound, I used "va" because it sounds pretty similar to a soft "th".
THEN for the "-mer" part in summer, the reason why i chose "me" + "a" is because (and this was personal preference!!) "suh-me-ah" sounds better to me than "summah" lmao.
ONE MORE THING!! super important -> trimming parts of the syllables out of the note! Instead of having the "st" in "story" being written out as "su to", i'd have it said as "s- to" by selecting the "su" note, going to tools > voice bank settings > duplicate, and use that duplicated note to go to > launch editor, and trim the vowel out. Then remember to change the alias to something different (so UTAU knows which version of "su" to use) and click "set", then "ok". Then re-enter the note with whatever you put for the alias. fat big brain.
---
wow this is sloppy but I hope it helps a bit!! I cover a lot of English songs so I get excited when I hear someone's trying to do just that :)
