Spell checking slides is easy when you're using the Litmos basic module editor.
Click the ABC spellchecker button circled below
The spellchecker will highlight misspelled words in yellow. Right clicking on the word will show a list of spelling corrections. In the case below we will select 'green' and the spell check is complete.
If your word is not recognised by the spellchecker and you know the spelling is correct you can add it to your own personal dictionary for future use by clicking "Add to dictionary"