It synthesizes singing exactly by simply typing in words and music notes on your PC. The sung vocal can be output as a Wav file, so it can be imported to other sequencers and played alongside the accompaniment.
Various styles of singing can be synthesized by adding further vocal libraries.
By changing database of "Vocaloid Singer Libraries", you can synthesize various types of male and female vocals. A number of soundware developers worldwide will release "vocal libraries" (some of which actually did) and the VOCALOID software engine is bundled into their library products.
Expressive effects can easily be added to the synthesized vocals in a simple operation.
Expressive effects can easily be added to the synthesized vocals, such as vibrato, inflection and tremolo, which are added by using the simple GUI commands, resulting in the creation of fully expressive songs.
Both Japanese and English vocals can be synthesized.
English and Japanese languages "vocal libraries" are now available.
The Technology
VOCALOID uses Frequency-Domain Singing Articulation Splicing and Shaping, a vocal (singing-voice) synthesizing system developed by Yamaha after lengthy reseach and development of signal processing in frequency domains. With this system, the "singing articulations" (collections of voice snippets, such as syllables and snippets of vocal expression variations, like vibrato) needed to reproduce vocals, are collected from custom-produced recordings of professional singers and put into a database after conversion into frequency domains. To synthesize vocal parts, the system retrieves data consisting of voice snippets, applies pitch conversion, then splices and shapes them to form the words of a song as typed by the user. As this processing is done at the frequency-domain level, pitch can be easily changed according to the specified melody, and the voice snippets can be spliced in a way that reproduces smooth-flowing words. For example, "sai" of "saita"is produced by using two snippets "sa" and "ai". Because the timbre of the vowels "a" and "ai" are usually different to each other, if these sounds were simply spliced together they would not sound right to the listener. To solve this problem, smooth processing of the splicing facility within the frequency domain is carried out, resulting in a smoother vocal.
Fig1. Processing within the frequency domain
In addition, conversion within the frequency domain makes it easy to control pitch and timbre in order to get expressive effects, such as vibrato. VOCALOID enables the reproduction of the actual pitch-time and timbre variations (accurately emulating the way they occured in the real singer's original vibrato) by storing the timbre/time variation of pitch and vibrato from the real singer's voice, into a database and applying it at the point of synthesis.
Fig 2. Process at vibrato
VOCALOID consists of a score editor which handles the scale, song-word, and expression processing; the Vocal Sound Generator (the engine that synthesizes the vocals); and vocal libraries (each comprised of a pronunciation database and a timbre database) for each virtual singer. The "vocal libraries" have been released by soundware developers who entered into a license agreement with Yamaha, and more libraries are coming.
Fig 3. VOCALOID system configuration
http://www.youtube.com/watch?v=lvM44DytTyE
für uns nicht so begabten
http://www.vocaloid.com/
auf sowas hab ich gewartet 
muss das den neu sein 
