Because of its small size and many languages, eSpeakNG is included in NVDA[2] open source screen reader for Windows, as well as Android,[3] Ubuntu[4] and other Linux distributions.

Its predecessor eSpeak was recommended by Microsoft in 2016[5] and was used by Google Translate for 27 languages in 2010;[6] 17 of these were subsequently replaced by proprietary voices.

In eSpeakNG's predecessor eSpeak, the initial versions of some languages were based on information found on Wikipedia.

In 1995, Jonathan Duddington released the Speak speech synthesizer for RISC OS computers supporting British English.

[9] On 17 February 2006, Speak 1.05 was released under the GPLv2 license, initially for Linux, with a Windows SAPI 5 version added in January 2007.

[18][19] The result of this was the creation of the espeak-ng (Next Generation) fork, using the GitHub version of eSpeak as the basis for future development.

[20] The first release of espeak-ng was 1.49.0 on 10 September 2016,[21] containing significant code cleanup, bug fixes, and language updates.

There are many languages (notably English) which do not have straightforward one-to-one rules between writing and pronunciation; therefore, the first step in text-to-speech generation has to be text-to-phoneme translation.

To add intonation for speech i.e. prosody data are necessary (e.g. stress of syllable, falling or rising pitch of basic frequency, pause, etc.)