VowSpace is an open-source desktop application for extracting, visualizing, normalizing, comparing, and analyzing vowel formant data from audio recordings and tabular datasets.

It provides an accessible graphical interface for common phonetic and sociophonetic workflows that might otherwise require custom scripts or several separate applications.

Quick links: Download VowSpace · Tutorials · Software paper · Changelog · Contributing · Report an issue

• Interactive vowel space plotting using F1, F2, and other selected measurements
• Acoustic analysis of audio files using Parselmouth and Praat
• Lobanov, Nearey1, Nearey2, and Bark Difference normalization
• Bark, Mel, ERB, and logarithmic frequency-scale transformations
• Speaker- and vowel-based grouping
• Ellipses, convex hulls, labels, color palettes, and other plot customization options
• Built-in DataFrame editor
• CSV and Excel import and export
• Publication-quality PNG, JPG, TIFF, SVG, and PDF plot export
• Built-in IPA keyboard

New to VowSpace? Follow the step-by-step tutorials.

VowSpace has been published in the Journal of Open Source Software. The paper describes the motivation behind the project, its main features, and its intended use in phonetic research.

Kaya, A. Ç. (2026). VowSpace: A vowel formant analysis application for phonetic research. Journal of Open Source Software, 11(120), 10189. https://doi.org/10.21105/joss.10189

Read the software paper.

VowSpace is available as a portable desktop application. Distributable builds are produced with Nuitka through the repository's build workflow.

1. Download the latest .dmg file from GitHub Releases.
2. Open the downloaded file.
3. Drag VowSpace into the Applications folder.
4. Launch VowSpace from Applications.

If macOS displays a security warning on first launch:

1. Right-click or Control-click the VowSpace application.
2. Select Open.
3. Confirm the macOS Gatekeeper prompt.

1. Download the latest .exe file from GitHub Releases.
2. Open the downloaded file to launch VowSpace.

1. Download the latest Linux executable from GitHub Releases.
2. If necessary, make the file executable:

chmod +x VowSpace

1. Launch it from your file manager or terminal.

The current Linux build has primarily been tested on minimal Debian and Fedora. Support for additional distributions and a more polished Linux experience are under active development. The application icon may not display correctly on some systems.

You can also clone the repository and run VowSpace directly from source. This is recommended for developers and researchers who want to inspect or contribute to the code.

git clone https://github.com/alicagank/VowSpace.git
cd VowSpace

VowSpace requires Python 3.10 or later. Its dependencies are declared in pyproject.toml.

uv automatically creates a virtual environment and installs the required dependencies on first run:

uv run vowspace

python3 -m venv .venv
source .venv/bin/activate
pip install .
vowspace

python -m venv .venv
.venv\Scripts\activate
pip install .
vowspace

The minimum dataset must contain the following columns:

The required columns are:

• vowel
• f1
• f2
• speaker

Additional measurements and derived columns, such as f0, f3, f4, f5, bark_f1, log_f1, and zsc_f1, are also supported where needed.

VowSpace can read and write:

• CSV files (.csv)
• Excel files (.xlsx, .xls)

Tabular data are handled with pandas, with Excel support provided through openpyxl.

VowSpace produces conventional vowel space plots with reversed F2 values on the horizontal axis and reversed F1 values on the vertical axis. However, all of this can be modified. Data from different speakers, sources, or groups can be distinguished using points, labels, colors, ellipses, and convex hulls.

Visualization settings allow users to customise:

• Color palettes
• Point size and transparency
• Labels
• Ellipses
• Convex hulls
• Filled, outlined, and circular styles
• Plot titles and other layout options

Normalization options are available through the Normalization Settings interface. VowSpace preserves the original data and applies one selected method at a time to prevent cumulative transformations.

Lobanov normalization reduces speaker-dependent anatomical variation by z-scoring each formant:

F_n[V] = (F_n[V] - MEAN_n) / S_n

The Bark Difference Metric transforms formant values to the Bark scale and calculates perceptual distances such as Z3–Z1 and Z2–Z1:

Z_i = 26.81 / (1 + (1960 / F_i)) - 0.53

Nearey1 subtracts the logarithm of a speaker-specific formant mean from each log-transformed value:

F_n[V] = log(F_n[V]) - log(mean(F_n_all_vowels))

Nearey2 uses a shared log mean across formants:

F_n[V] = log(F_n[V]) - mean(log(F_1, F_2, ..., F_n))

VowSpace also supports the following transformations:

Log

F_log = log10(F)

Mel

F_mel = 2595 × log10(1 + F / 700)

Bark

Z = 26.81 / (1 + 1960 / F) - 0.53

ERB

F_erb = 21.4 × log10(1 + 0.00437 × F)

The implementations draw on established methods in vowel normalization and on open resources such as Remirez (2022) and the phonR package.

Audio Analysis Tools is a separate window accessible from the main interface. It uses Parselmouth, a Python interface to Praat, to display and measure:

• Intensity
• Pitch
• Vowel formant frequencies from F1 to F5

Users can add measured formant frequencies directly to the main visualizer by right-clicking the plot in the Audio Analysis Tools window.

Higher formants can be unstable in some recordings. Depending on recording quality and environment, F5 may be returned as NaN. Measurements can be reviewed and edited in the DataFrame Editor, or repeated when necessary.

Supported audio formats include:

• WAV (.wav)
• FLAC (.flac)
• AIFF and AIFC (.aiff, .aif, .aifc)
• MP3 (.mp3)
• OGG (.ogg)

Intensity

Pitch

Vowel formant frequencies

The DataFrame Editor allows users to make small adjustments to the current dataset without opening another application. Saving changes automatically updates the plot. Edited data can also be exported as a separate spreadsheet using Save Data As….

The Export Plot dialog supports PNG, JPG, TIFF, SVG, and PDF output. Its live preview shows how changes to DPI, pixel dimensions, and layout settings affect the exported figure.

VowSpace includes a dedicated IPA keyboard for entering vowel symbols directly within the application.

See CHANGELOG.md for detailed release notes.

Feedback, bug reports, feature requests, and descriptions of research workflows directly help improve VowSpace.

If you have used the application, you are welcome to complete the anonymous feedback form.

For support:

• Read the tutorials.
• Visit the VowSpace project page.
• Open an issue and include your operating system, Python version, error messages, screenshots, and the expected behavior where possible.

Contributions, bug fixes, documentation improvements, and feature proposals are welcome. :) Please read CONTRIBUTING.md before submitting a pull request.

VowSpace is independently developed and maintained, so thoughtful issue reports and contributions are especially valuable.

VowSpace is actively developed and tested, but users should independently verify its outputs before relying on them in research or publications.

This application is provided as is, without warranty of any kind, express or implied. The developer assumes no responsibility for errors, inaccuracies, or consequences arising from the use of the software or its outputs.

Please cite VowSpace as:

Kaya, A. Ç. (2026). VowSpace: A vowel formant analysis application for phonetic research. Journal of Open Source Software, 11(120), 10189. https://doi.org/10.21105/joss.10189

BibTeX:

@article{kaya2026vowspace,
  author  = {Kaya, Ali Çağan},
  title   = {VowSpace: A vowel formant analysis application for phonetic research},
  journal = {Journal of Open Source Software},
  year    = {2026},
  volume  = {11},
  number  = {120},
  pages   = {10189},
  doi     = {10.21105/joss.10189}
}

The methodological background and full reference list are available in the JOSS software paper. The implementation also draws on established work in vowel plotting, normalization, auditory scales, Matplotlib, pandas, NumPy, SciPy, Parselmouth, and Praat.

VowSpace is distributed under the GNU General Public License v3.0.

For downloads, examples, and further information, visit the VowSpace project page or the repository's Releases page.