UTAU is a Japanese singing synthesizer application created by Ameya/Ayame. This program is similar to the VOCALOID software, with the difference being it is shareware instead of under a third party licensing. In March 2008, Ameya/Ayame released UTAU, a free, advanced support tool shareware software that was made free-to-download from its main website. UTAU (歌う), meaning "to sing" in Japanese, has its origin in the activity of "Jinriki Bōkaroido" (人力ボーカロイド, Manual Vocaloid), where people edit an existing vocal track, extract phonemes, adjust pitch, and reassemble them to create a Vocaloid-esque singing voice. UTAU was originally created to assist this process using concatenative synthesis. UTAU has the ability to use WAV files provided by the user, so that a singing voice can be synthesized by introducing song lyrics and melody. It comes with AQUEST's voice synthesizer "AquesTalk" for synthesizing the voice samples of the default voicebank, Utane Uta (also nicknamed Defoko) on UTAU's initial launch, after which the generator deletes itself. Voices made for the UTAU program are officially called "UTAU" as well, though they are colloquially known as "UTAUloids", a reference to VOCALOID. They are also called "voicebanks" (more common in English-speaking areas) and "(voice) libraries" in Japan. A myriad number of voicebanks have been developed by independent users. These voicebanks are normally distributed directly from their creators via internet download.

UTAU is mostly a Japanese program and thus many voices are created specifically for the Japanese language. However, the languages have been expanded and there are many bilingual UTAUloids, mostly singing in Japanese and English. While there are a high number of bilingual UTAU, multilingual UTAU have also been made that can sing in three or more languages. Regardless of the language, the software menus remain in Japanese and a user's computer must be in the Japanese locale or use AppLocale in order to run the software. Most of its documentation is in Japanese, but its User Manual has been translated into English. Recently, the program has been user translated to English, and other translations are still pending. However, even with the translations, the program still requires support for Japanese text.

UTAU's project files are saved under the ".ust" (Utau Sequence Text) extension. These files can be freely distributed, allowing different UTAU to sing the same piece. It is important to make note of the guidelines the UST creator has provided in terms of the .ust's distribution and use. Producers have developed several methods of producing their sound banks and results for the voicebanks vary because of this.

Ameya/Ayame added support for Unicode in an unreleased newer version of UTAU as per the screenshots posted on her Twitter. The corresponding backend support tail fixed region as well as several other audio encodings has already been release, while frontend support is yet to be released as of September 2020.

SOURCE: WIKPEDIA