Lots of work, especially for English (as opposed to Japanese which has many fewer possible morae/sounds [1]). I've made a number of (as yet unreleased [2]) song

Lots of work, especially for English (as opposed to Japanese which has many fewer possible morae/sounds [1]). I've made a number of (as yet unreleased [2]) song covers with the Kumi Hitsuboku English voice bank [3], which boasts the most expressive English reclist ("recording list" of individual recorded syllable fragments) I've seen. To get believable pronunciation, you can't just one-to-one map between a note and a pitch-shifted sound. Many syllables need to be broken into one note containing the starting consonant and the held vowel, sometimes another note containing a vowel transition (for example, the long "i" needs to be broken into a short "a" and a long "e"), and another note containing the end of the word (a vowel blended into a consonant). And in English, sometimes you need to work the previous word into the first note: for instance, "come on" becomes "ka," "ma," "a n" in Kumi's aliased reclist. UTAU doesn't do anything algorithmic to help with these word-splitting tasks; even if it could, there's a lot of nuance and judgement that depends on everything from the tempo to the specific vocalist's pronunciation. For instance, the word "slam" is actually best rendered as "sle, e m" when working with Kumi because the "a" sound is more hollow, and the point at which you switch from the "sle" to the "e m" depends a lot on context. A 2-minute song with chorus and verses can take hours to get perfect. And of course, pronunciation is only the beginning. Mitchie M (one of the most highly regarded vocaloid artists, mentioned elsewhere in this thread) stated in an interview that he can spend up to 2 weeks programming intonations for rap segments in his songs. [4] It's very interesting to think about how spoken word would be coded as pitches, and how we are able to detect deviations from common pitch-patterns as "unnatural" when listening to spoken passages. [1] See http://en.wikipedia.org/wiki/Katakana http://en.wikipedia.org/wiki/Katakana [2] Why unreleased? Still working on making lyric videos to accompany the recordings; for that, I need to shut down my VMs to launch After Effects, and I can't justify procrastinating that much! [3] Links at http://utau.wikia.com/wiki/Kumi_Hitsuboku http://utau.wikia.com/wiki/Kumi_Hitsuboku [4] https://www.facebook.com/vocaloidism/posts/568055823290010 https://www.facebook.com/vocaloidism/posts/568055823290010