Mbrola is Thierry Dutoit's phonemizer for multilingual speech synthesis. The various diphone databases are distributed on separate packages, but they must be used with and only with Mbrola because of license matters. Read the copyright for details.

Mbrola itself doesn't provide full TTS. It is a speech synthesizer based on the concatenation of diphones. It takes a list of phonemes as input, together with prosodic information (duration of phonemes and a piecewise linear description of pitch), and produces speech samples on 16 bits (linear), at the sampling frequency of the diphone database.

Use Mbrola along with Freephone, cicero or espeak to have a complete text-to-speech in English.