This directory is coming straight from the ProjectorRays project
https://github.com/ProjectorRays/ProjectorRays/tree/master/src/lingodec
And should be kept in sync.
At the time of writing, the changes have not yet been merged within ProjectorRays and as such, live in 'scummvm' branch:
https://github.com/ProjectorRays/ProjectorRays/tree/scummvm/src/lingodec
The original code is licensed under the Mozilla Public License 2.0.