Acknowledgements

• FlorisBoard

  Duoboard’s swipe classifier is a modified Swift port of FlorisBoard’s statistical glide typing classifier. Copyright © 2025 The FlorisBoard Contributors. Licensed under the Apache License 2.0.

• SymSpell

  The word list is built from SymSpell’s English frequency dictionary. Copyright © 2018 Wolf Garbe. MIT License.

• Google Books Ngram

  SymSpell’s word frequencies come from Google Books Ngram data, licensed under CC BY 3.0. Duoboard filters, truncates and re-ranks them.

• SCOWL

  SymSpell’s vocabulary was filtered against SCOWL. Copyright 2000–2019 by Kevin Atkinson, used under its permission notice, which includes the UKACD notice. github.com/en-wl/wordlist.

The Duoboard app lists these under Settings → Acknowledgements, with the Apache License in full.