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An interface to ISLEX, an IPA pronunciation dictionary for English with stress and syllable markings.

Project description


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Pronounced like 'p' + 'isle'.

An interface to a pronunciation dictionary with stress markings (ISLEX - the international speech lexicon), along with some tools for working with comparing and aligning pronunciations (e.g. a list of phones someone said versus a standard or canonical dictionary pronunciation).

Table of contents

  1. Documentation
  2. Common Use Cases
  3. Version History
  4. Requirements
  5. Optional resources
  6. Installation
  7. Example usage
  8. Citing psyle
  9. Acknowledgements


Automatically generated pdocs can be found here:

Common Use Cases

What can you do with this library?

  • look up the list of phones and syllables for canonical pronunciations of a word

  • map an actual pronunciation to a dictionary pronunciation (can be used to automatically find speech errors)

    pronunciationtools.findClosestPronunciation(isleDict, 'cat', ['k', 'æ',])
  • automatically syllabify a praat textgrid containing words and phones (e.g. force-aligned text) -- requires the praatIO library

    pysle.syllabifyTextgrid(isleDict, praatioTextgrid, "words", "phones")
  • search for words based on pronunciation

    isletool.LexicalTool('ISLEdict.txt').search('dVV') # Any word containing a 'd' followed by two vowels

    e.g. Words that start with a sound, or have a sound word medially, or in stressed vowel position, etc.

    see /tests/

Version History

Pysle uses semantic versioning (Major.Minor.Patch)

Ver 2.3 (Nov 18, 2020)

  • add exactMatch to
    • when True, will return exact phonetic matches, ignoring stress, syllable, and word markers
    • see examples/

Ver 2.2 (Nov 17, 2020)

  • the ISLEdict is now bundled with pysle--no need to download it separately!
  • loading the isleDict is ~10% faster

Ver 2.1 (May 31, 2020)

  • add transcribe function, given a word or series of words, get a possible pronunciation;
    • see examples/

Ver 2.0 (May 27, 2020)

  • cleaned up the api a little, including some functions that weren't usable
  • updated documentation and readme files. Added pdoc documentation

Ver 1.5 (March 3, 2017)

  • substantial bugfixes made, particularly to the syllable-marking code

Ver 1.4 (July 9, 2016)

  • added search functionality
  • ported code to use the new unicode IPA-based isledict
    • (the old one was ascii)
  • (Oct 20, 2016) Integration tests added; using Travis CI and Coveralls
    • for build automation. No new functionality added.

Ver 1.3 (March 15, 2016)

  • added indicies for stressed vowels

Ver 1.2 (June 20, 2015)

  • Python 3.x support

Ver 1.1 (January 30, 2015)

  • word lookup ~65 times faster

Ver 1.0 (October 23, 2014)

  • first public release.


  • Python 2.7.* or above

  • Python 3.7.* or above (or below, probably)

Click here to visit travis-ci and see the specific versions of python that pysle is currently tested under

  • The praatIO library is required IF you want to use the textgrid functionality. It is not required for normal use.

Optional resources

pysle requires the ISLEdict pronunciation dictionary (copyright Mark Hasegawa-Johnson, licensed under the MIT open source license). This is bundled with psyle. However, you may want to use a subset of the pronunciations or you may want to add your own pronunciations.

In that case, please get the original file.

ISLEX github page

Direct link to the ISLEX file used in this project (ISLEdict.txt)

See examples/ for an example of how to load a custom ISLEdict file.


Pysle is on pypi and can be installed or upgraded from the command-line shell with pip like so

python -m pip install pysle --upgrade

Otherwise, to manually install, after downloading the source from github, from a command-line shell, navigate to the directory containing and type

python install

If python is not in your path, you'll need to enter the full path e.g.

C:\Python36\python.exe install

Example usage

Here is a typical usage

from pysle import isletool
isleDict = isletool.LexicalTool('C:\islev2.dict')
print(isleDict.lookup('catatonic')[0]) # Get the first pronunciation
# >> (([['k', 'ˌæ'], ['ɾ', 'ə'], ['t', 'ˈɑ'], ['n', 'ɪ', 'k']], [2, 0], [1, 1]),)

and another

from pysle import isletool
from pysle import pronunciationtools

isleDict = isletool.LexicalTool('C:\islev2.dict')

searchWord = 'another'
phoneList = ['n', '@', 'th', 'r'] # Actually produced (ASCII or IPA ok here)

returnList = pronunciationtools.findBestSyllabification(isleDict, searchWord, phoneList)
syllableList = returnList[2]
# >> [["''"], ['n', '@'], ['th', 'r']]

Please see \examples for example usage

Citing pysle

Pysle is general purpose coding and doesn't need to be cited (you should cite the ISLEX project instead) but if you would like to, it can be cited like so:

Tim Mahrt. Pysle., 2016.


Development of Pysle was possible thanks to NSF grant IIS 07-03624 to Jennifer Cole and Mark Hasegawa-Johnson, NSF grant BCS 12-51343 to Jennifer Cole, José Hualde, and Caroline Smith, and to the A*MIDEX project (n° ANR-11-IDEX-0001-02) to James Sneed German funded by the Investissements d'Avenir French Government program, managed by the French National Research Agency (ANR).

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