I added a spell checker to V2.4.40 of SlideMagic. Incorrectly spelled words get a little underlining, right clicking gives you access to some spelling suggestions, and the option to add a correctly spelled word to the library.

This feature was high on the list of priorities of my daughter, who is using SlideMagic a lot for school projects.

Photo by Edurne Chopeitia on Unsplash