Afaict, two letter words just aren't worth the effort of spell checking.
I will take implementation feedback. But, prerelease now, and 0.0.18-alpha (when it's released), by default, will not complain about two letter words.
See Autodetect valid word lengths for more information.
FAQ | Showcase | Event descriptions | Configuration information | Known Issues | Possible features | Deprecations | Release notes | Helpful scripts