Cadencii is a voice synthesizer program, using VOCALOID, VOCALOID2, UTAU, STRAIGHT with UTAU, and AquesTone as synthesizers. It is currently officially available for Windows, Mac OS X, Debian-based systems, and openSUSE. The latest version available is v3.5.1 for Windows, v3.4.1 for Mac OS X, and v3.3.9 for Debian-based systems.
During the first time it is used, an UTAU/Vocaloid might have an error playing an UST or VSQ. Its voice is not quite clear. This program is compatible with English and Japanese. If you have the required environment for the program, it is able to sound very realistic.
Besides the Windows and Mac binaries, Cadencii can also be launched with the latest version of mono, allowing Cadencii to be able to run on the many platforms supported by mono. Several functions using VOCALOID2 VSTi may not work properly, however. Mono is available for download here.