For a few suggestions of what to contribute you can check the issues of the project.
I will try to merge any pull request as long as it doesn't break something. For how to submit a pull request you can check the official documentation
If you want to contribute more annotated words you can do so by submitting a separate csv file compressed in a zip folder. Format should be the same as the format of the csv file I have submitted, unless you want to annotate words in a different way, e.g. annotate words for whether they have Latin root. In case you choose to annotate something else, explain it in your pull request.