The Mbrola project is a collection of diphone voices for speech synthesis. They do not include any text-to-phoneme translation, so this must be done by another program. The Mbrola voices are cost-free but are not open source. They are available from the Mbrola website at:

eSpeak can be used as a front-end to Mbrola. It provides the spelling-to-phoneme translation and intonation, which Mbrola then uses to generate speech sound.

Voice Names

To use a Mbrola voice, eSpeak needs information to translate from its own phonemes to the equivalent Mbrola phonemes. This has been set up for only some voices so far.

The eSpeak voices which use Mbrola are named as:

where xxx is the name of a Mbrola voice (eg. mb-en1 for the Mbrola "en1" English voice). These voice files are in eSpeak's directory espeak-data/voices/mbrola.

The installation instructions below use the Mbrola voice "en1" as an example. You can use other mbrola voices for which there is an equivalent eSpeak voice in espeak-data/voices/mbrola.

There are some additional eSpeak Mbrola voices which speak English text using a Mbrola voice for a different language. These contain the name of the Mbrola voice with a suffix -en. For example, the voice mb-de4-en will speak English text with a German accent by using the Mbrola de4 voice.

Windows Installation

The SAPI5 version of eSpeak uses the mbrola.dll.
  1. Install eSpeak. Include the voice mb-en1 in the list of voices during the eSpeak installation.

  2. Install the PC/Windows version of Mbrola (MbrolaTools35.exe) from:

  3. Get the en1 voice from: unpack the archive, and copy the "en1" data file (not the whole "en1" directory) into C:/Program Files/eSpeak/espeak-data/mbrola.

  4. Use the voice espeak-MB-EN1 from the list of SAPI5 voices.

Linux Installation

From eSpeak version 1.44 onwards, eSpeak calls the mbrola program directly, rather than passing phoneme data to it using a pipe.
  1. To install the Linux Mbrola binary, download: Unpack the archive, and copy and rename the file from: mbrola-linux-i386 to mbrola somewhere in your executable path (eg. /usr/bin/mbrola ).

  2. Get the en1 voice from: Unpack the archive, and copy the "en1" data file (not the whole "en1" directory) to /usr/share/mbrola/en1.

    eSpeak will look for mbrola voices firstly in espeak-data/mbrola and then in /usr/share/mbrola

  3. If you use the eSpeak voice such as "mb-en1" then eSpeak will use the mbrola "en1" voice, eg:
    espeak -v mb-en1 "Hello world"

    To generate mbrola phoneme data (.pho file) you can use:
    espeak -v mb-en1 -q --pho "Hello world"
    espeak -v mb-en1 -q --pho --phonout=out.pho "Hello world"

Mbrola Voice Files

eSpeak's voice files for Mbrola voices are in directory espeak-data/voices/mbrola. They contain a line:
  mbrola <voice> <translation>
  mbrola en1 en1_phtrans They are binary files which are compiled, using espeakedit, from source files in phsource/mbrola, see below.

Mbrola Phoneme Translation Data

Mbrola phoneme translation files specify translations from eSpeak phoneme names to mbrola phoneme names. They are referenced from voice files.

The source files are in phsource/mbrola. These are compiled using the espeakedit program (Compile->Compile mbrola phonemes list) to produce data files in espeak-data/mbrola_ph which are used by eSpeak.

Each line in the mbrola phoneme translation file contains:

<control> <espeak ph1> <espeak ph2> <percent> <mbrola ph1> [<mbrola ph2>]

The list is searched from start to finish, until a match is found. Therefore, a line with more specific match condition should appear before a line which matches the same eSpeak phoneme but with a more general condition.

The file dictsource/dict_phonemes lists the eSpeak phonemes which are used for each language. Translations for all these should be given in the mbrola phoneme translation file. In addition, some phonemes which are referenced from phoneme files (eg. phsource/ph_language, phsource/phonemes) in lines such as:

   beforenotvowel   l/
   reduceto  a#  0
should also be included, even though they don't appear in dictsource/dict_phonemes.

If the language's *_list or *_rules files includes rules to speak words "as English" the mbrola phoneme translation file should include rules which translate English phonemes into near equivalents, so that they can spoken by the mbrola voice.