Researchers from the IBM have developed new technology of computer generated voice that much more resembles to the human voice.

Vibrato -- the pulsating change of pitch in a singer’s voice -- is an important aspect of a singer’s expression, used extensively by both classical opera singers and pop stars like Shakira. Usually, the quality of a vibrato can only be judged subjectively by voice experts.

A major function of speech is the communication of intentions. In everyday conversation between adults, intentions are conveyed through multiple channels, including the syntax and semantics of the language, but also through nonverbal vocal cues such as pitch, loudness, and rate of speech.