Chances are you have probably seen a singing character with long, blue pigtails right? That cutie has a name: Hatsune Miku. In reality, there is no living person like Hatsune Miku, but voices like hers are made possible by modern technology. Vocaloid is a software that allows songwriters to have an artificial singing voice, completely programmable and able to replace a human singer.
Before vocaloid, there was a predecessor called vocoder. Vocoders were often part of the synthesizer, (such as the modern Microkorg) musicians would sing (or talk) into the microphone while simultaneously playing the desired vocal notes on the keys. This was ideal for live band performances, and the technology has been made popular by artists like Peter Frampton and Michael Jackson’s “P.Y.T. (Pretty Young Thing).”
Vocaloid is primarily edited using a computer, by typing in the lyrics and melody. Downloading the software means that the voice data has already been recorded by professional singers or voice actors, rather than that coming from you. It was first made available in Japanese language, but has since released some English, Korean, Chinese, and Spanish support for some of the characters.