QuidiVidi is a non-indexing side project of Picardy Indexing. It is used to analyze linguistic transcripts encoded in CHAT format.

You can use QuidiVidi to calculate:

• MLU (mean length of utterance), MLT, MLU5
• Word/morpheme frequencies
• Brown’s morphemes counts
• Lexical class percentages (nouns, verbs, etc.)
• Maximum length of words/utterances
• Comparisons between tokens on different CHAT tiers
• Distribution of words, utterances, and turns of various lengths
• Lexical diversity

You can also filter the input on tier-specific search terms.

QuidiVidi is available for Windows™, Macintosh™, and Linux. Your feedback is welcomed (picardy.indexing@gmail.com)! Bug reports and feature requests may be incorporated into future releases.

Terms and conditions

QuidiVidi is free of charge and freely distributable. The source code will not be made available. QuidiVidi is licensed under Creative Commons Attribution 4.0 International. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/ (I’m not a lawyer, but my interpretation of the license is that, basically, you don’t have to pay me anything to download and use the software, and I can’t be held liable if the software doesn’t work the way you expect. Furthermore, you can redistribute and/or repackage the software into a product of your own but you need to give me credit.)

Downloads

Click below to download an installer for the appropriate platform.

Look here if you have problems downloading and/or running the installer.

Note for Macintosh and Linux users: QuidiVidi toolbar buttons use the Segoe MDL2 Assets font; Windows has this font installed by default, but for Macintosh and Linux you will need to install it before using the software. You can download this font from Microsoft here. Look here if you need instructions for installing fonts in Linux.

Windows (.exe; 32MB; uploaded February 20, 2026)

Linux (tar.gz; 77MB; uploaded February 21, 2026)

Macintosh (.zip; 39MB; uploaded February 21, 2026)