How to change wrong English sentences in contributed module?
Another approach is to use GIT for such contributed modules to actually change such sentences or words. E.g. with the master branch corresponding to the official version of such module, and a branch containing all the changes.

In doing so, it is straight forward to also create a PATCH each time such changes are needed, which you can then also attach to an issue in the issue queue to report about such changes. Bonus: you're contributing to Drupal! ... Which should also show up in your D.O profile ... By creating such "issue" (in the module's issue queue, the module maintainers will get notified automatically (unless they turned of such notifications for their modules). So that's "a" way to contact the maintainer/contributor. Refer to comment #1 in issue # 2327917 for a contributed patch containing only a 1 character typo correction (remove an "s" that was not appropriate), and which I committed afterwards.

If you're not able or willing to create such patch, then at least "report" about it in the issue queue, even if it is only some small issue (in the format of a few lines or text about the typo to be corected). Such issues should get picked up soon by the module maintainers (who will transform that in a patch, etc).

And next time the module gets updated, you use GIT to also update the master branch of that module in your own site. After doing so, you then also use GIT to re-apply all relevant changes that are needed for the new version again. For patches that got accepted in the official version of the module, you won't need to reapply their changes anymore of course.

With this approach, you've reduced your issue to something like maintaining a custom version of a module, and at the same time you're contributing to a permanent solution to reduce the need for such changes in the future.