Acknowledgments

The following people contributed source code to Praat:

  Paul Boersma: user interface, graphics, printing, sound, spectral analysis, pitch analysis, formant analysis, intensity analysis, annotation, speech manipulation, voice report, listening experiments, articulatory synthesis, optimality-theoretic learning, tables, formulas, scripting, and adaptation of PortAudio, GLPK, regular expressions, eSpeak, Opus, LAME, Blake3 and Zlib.
  David Weenink: feedforward neural networks, principal component analysis, multidimensional scaling, discriminant analysis, LPC, Acoustic synthesis (Klatt), automatic alignment, VowelEditor, FormantPath, and adaptation of GSL, LAPACK, fftpack, regular expressions, eSpeak, Ogg Vorbis, Opus and LAME.
  Anastasia Shchupak: automatic speech recognition with word-level timestamps, automatic speaker diarization, and adaptation of whisper.cpp, Silero VAD and pyannote.audio.
  Erez Volk: adaptation of FLAC and MAD.
  Stefan de Konink and Franz Brauße: major help in port to GTK.
  Tom Naughton: major help in port to Cocoa.
  Ola Söder: kNN classifiers, k-means clustering.
  Rafael Laboissière: adaptation of XIPA, audio bug fixes for Linux.
  Darryl Purnell created the first version of audio for Praat for Linux.

We included the following freely available software libraries in Praat (sometimes with adaptations):

  XIPA: IPA font for Unix by Fukui Rei (GPL).
  GSL: GNU Scientific Library by Gerard Jungman and Brian Gough (GPL 3 or later).
  GLPK: GNU Linear Programming Kit by Andrew Makhorin (GPL 3 or later); contains AMD software by the same author (LGPL 2.1 or later).
  PortAudio: Portable Audio Library by Ross Bencina, Phil Burk, Bjorn Roche, Dominic Mazzoni, Darren Gibbs, version 19.7.0 of April 2021 (CC-BY-like license).
  eSpeak(-NG): text-to-speech synthesizer by Jonathan Duddington and Reece Dunn, development version 1.52 of August 2023, with language and voice data of 2024-08-24T19:38Z (GPL 3 or later).
  MAD: MPEG Audio Decoder by Underbit Technologies (GPL 2 or later).
  LAME: MP3 encoding by Mike Cheng, Mark Taylor, Takehiro Tominaga, Robert Hegemann, Gabriel Bouvigne, Alexander Leidinger, Naoki Shibata, John Dahlstrom, Jonathan Dee, Rogério Brito, Frank Klemm, Don Melton, Albert L. Faber, Roberto Amorim, Josep Maria Antolín Segura, Dominique Duvivier, Joseph Flynn, Peter Gubanov, Guillaume Lessard, Steve Lhomme, Darin Morrison, Dyle VanderBeek, David Robinson, Glen Sawyer, Marcel Muller, Olcios, version 3.100 of October 2017 (GPL 2 or later).
  FLAC: Free Lossless Audio Codec by Josh Coalson and Xiph.Org, version 1.5.0 of February 2025 (FLAC BSD 3-clause license).
  Ogg Vorbis: audio compression by Christopher Montgomery (Ogg Vorbis BSD 3-clause license).
  Opus: audio compression by Jean-Marc Valin, Gregory Maxwell, Christopher Montgomery, Timothy Terriberry, Koen Vos, Andrew Allen and others (Opus BSD 3-clause license).
  SILK: audio compression by Skype Limited (Skype Limited BSD 3-clause license).
  fftpack: public-domain Fourier transforms by Paul Swarztrauber, translated to C by Christopher Montgomery.
  LAPACK: public-domain numeric algorithms by Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., Courant Institute, Argonne National Lab, and Rice University, C edition by Peng Du, Keith Seymour and Julie Langdou, version 3.2.1 of June 2009.
  Regular expressions by Henry Spencer, Mark Edel, Christopher Conrad, Eddy De Greef (GPL 2 or later).
  Unicode Character Database by Unicode Inc., version 16.0 of August 2024 (Unicode Inc. license agreement).
  Quickselect and Median of ninthers, by Andrei Alexandrescu 2016 (Boost Software License 1.0).
  ggml: tensor library for machine learning by Georgi Gerganov and many others, version 0.9.7 (ggml MIT License)
  whisper.cpp: automatic speech recognition, by Georgi Gerganov and many others, version 1.8.3 (whisper.cpp MIT License), using separately installed Whisper models by OpenAI (Whisper OpenAI MIT License).
  Silero VAD: speech activity detection model by Silero Team, version 6.2.0 of November 2025 (Silero VAD MIT License).
  pyannote.audio: automatic speaker diarization toolkit by Hervé Bredin, version 4.0.4 of February 2026 (pyannote.audio MIT License).
  WeSpeaker: speaker embedding learning toolkit by WeNet Community, version 1.2.0 of July 2023 (WeSpeaker Apache License 2.0), using speaker embedding model trained on VoxCeleb2 speaker recognition dataset by Joon Son Chung, Arsha Nagrani and Andrew Zisserman (VoxCeleb CC-BY-4.0 license).
  Blake3: cryptographic hashes by Jack O’Connor, Samuel Neves, Jean-Philippe Aumasson and Zooko (CC0 1.0).
  zlib: compression by Jean-loup Gailly and decompression by Mark Adler (Zlib license), version 1.3.2.1 of 17 February 2026.

Our own parts of the source code of Praat are distributed either under the General Public License, version 2 or later, or under the General Public License, version 3 or later. Because of this, combined with the inclusion of the above software written by others, the whole of Praat is distributed under the General Public License, version 3 or later.

For their financial support during the development of Praat:

  Netherlands Organization for Scientific Research (NWO) (1996–1999).
  Nederlandse Taalunie (2006–2008).
  Talkbank project, Carnegie Mellon / Linguistic Data Consortium (2002–2003).
  Stichting Spraaktechnologie (2014–2016).
  Spoken Dutch Corpus (CGN) (1999–2001).
  Laboratorium Experimentele OtoRhinoLaryngologie, KU Leuven.
  DFG-Projekt Dialektintonation, Universität Freiburg.
  Department of Linguistics and Phonetics, Lund University.
  Centre for Cognitive Neuroscience, University of Turku.
  Linguistics Department, University of Joensuu.
  Laboratoire de Sciences Cognitives et Psycholinguistique, Paris.
  Department of Linguistics, Northwestern University.
  Department of Finnish and General Linguistics, University of Tampere.
  Institute for Language and Speech Processing, Paradissos Amaroussiou.
  Jörg Jescheniak, Universität Leipzig.
  The Linguistics Teaching Laboratory, Ohio State University.
  Linguistics & Cognitive Science, Dartmouth College, Hanover NH.
  Cornell Phonetics Lab, Ithaca NY.

Finally we thank:

  Ton Wempe and Dirk Jan Vet, for technical support and advice.
  Daniel Hirst and Daniel McCloy, for managing the Praat Users List.
  Rafael Laboissière and Andreas Tille, for maintaining the Debian package.
  Jason Bacon and Adriaan de Groot, for maintaining the FreeBSD port.
  Anna Simmons, for maintaining the Flathub package.
  José Joaquín Atria and Ingmar Steiner, for setting up the source-code repository on GitHub.
  Hundreds of Praat users, for sending suggestions and notifying us of problems and thus helping us to improve Praat.

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