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FLEx (FieldWorks Language Explorer)

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FieldWorks Language Explorer (FLEx) is the lexical and text tools component of SIL FieldWorks. It is an open source desktop application designed to help field linguists perform many common tasks. It can help you:

  • record and manage lexical information
  • configure and export dictionaries (we recommend Pathway)
  • interlinearize texts
  • analyse discourse features
  • study morphology
  • collect and organize cultural and other notes
  • send/receive which supports remote collaboration.

 To see many of the features of FLEx before you download and install it, view the demo movies.






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SIL Status


Supported Operating Systems

Linux, Windows, Windows XP, Windows XP x64, Windows Vista, Windows Vista x64, Windows 7, Windows 8, Windows 10

Unicode Support


Suitable tasks

  • Collect word lists using IPA transcription and/or audio recording
  • Identify the most frequently used words in a natural text corpus
  • Store and edit an electronic data notebook of cultural events in a form conducive to qualitative analysis
  • Easily mark and search for events using standardized codes (OCM codes or custom codes, etc.)
  • Record and play back utterances as electronic audio
  • Store and edit an electronic notebook of language data in a form conducive to analysis
  • Create and edit a lexical database (modeling morphology if necessary)
  • Validate the structure of lexical data
  • Create and edit a corpus of natural texts
  • Collect, transcribe and translate audiorecordings of natural texts (and other texts/utterances)
  • From the text corpus, look up words in the lexicon
  • Populate the lexical database using rapid data entry (e.g. DDP)
  • Interlinearize natural texts, sharing glosses with a lexical database
  • Interlinearize natural texts without a lexical database
  • Work with lexical data arranged by root (root-based rather than stem-based)
  • Define dictionary entries while grouping them together by semantic domain
  • Run a concordance search to find all occurrences of a given word in a text corpus
  • Supply additional information such as word category, example sentences, lexical relations
  • Test the text corpus against the grammar (e.g. the syntax or discourse)
  • Analyze the discourse structure of each type of discourse in the corpus
  • Organize a grammar for publication
  • Publish linguistic data (e.g. phonetic data and interlinear texts)
  • Interlinearize the translation, glossing it in an LWC
  • Create back-translations in an LWC
  • Localizable (i.e. user interface can be translated)
  • Compare/merge edits to the same data across multiple computers
  • Version control and backups
  • With support for multiple scripts
  • With support for complex non-Roman scripts
  • Store data in a standardized XML format
  • Archive data in Unicode in a long-life file format (e.g. XML)
  • Check spelling
  • Check grammar
  • Convert data between Unicode and legacy encodings
  • Convert between formats (e.g. SFM and XML)
  • Convert legacy fonts into Unicode fonts
  • Do research, look up information
  • A useful template (e.g. for a research grant proposal or linguistic paper, etc.)
  • Other

Interface Language

English, French, Hindi, Portuguese, Russian, Spanish, Bahasa Indonesian, Bahasa Malaysia, Korean, Persian, Mandarin Chinese, Turkish, Telegu


Open Source

Download Page


User Group


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Flex is very powerful, but requires a lot of learning. It also requires some programming in order to match the characteristics of the language or language family for which it is being used.


I would say it needs to be configured to the language, but "programming" applies something that the average person couldn't do on their own. I don't find that to be the case at all. Secondly, the basic data entry of new words does not require much learning. However, the deeper you go into the grammar of a language, the more learning is required to make use of the capabilities of FLEx.

Resolution of Thanks

The Linguistics Consultants Roundtable, Amercas Area, Catalina, Arizona, September 25, 2009: We want to formally express our deep appreciation to you, the developers of FieldWorks Language Explorer. FLEx has so many wonderful and detailed features that will be incredibly helpful to us in analyzing local languages in the Americas…We also thank you for being so very helpful when we have questions or other issues. We know that your work is largely out of the public eye, and even out of the view of most SIL people, but we are very grateful for your persistence in creating new features, working out bugs, and the whole development process. Thank you!

application | by Dr. Radut