The ScreenSteps desktop editor has spell check built in. You can either check spelling as a one-time event, or you can check spelling as you type.
On macOS the language that is being spell checked will be determined automatically. On Windows you can select from one of the pre-installed spell check dictionaries.
Check Spelling (one-time check)
Click on Edit > Spelling > Check Spelling
Check Spelling While Typing
You can also turn on spellcheck so that it checks spelling as you type, and underlines misspelled words.
Click Edit > Spelling > Check Spelling While Typing.
This is only applicable on Windows
On Windows you can select which language dictionary should be used to spell check articles. Make your selection from the Edit > Spelling > Spelling Dictionary menu.