I'm working on my Drupal-based website using CKEditor and I need to enable some sort of spell checking for the CKEditor. Do you have any idea how can I achieve this?
CKEditor has a built-in spell checker, that implements uses WebSpellChecker.net as its dictionary and it should be enabled by default in CKEditor installation for Drupal.
If it's not go to admin/config/content/ckeditor and check your settings.
Spell-checker options and their buttons should be visible in the editing box as the "ABC" buttons in the left-top corner.
Using the button with the drop-down menu you can also select your language, backend dictionary and the method of spell-checking (e.g. SCYAT, Spell Check As You Type), which is very similar to that one used in Word, Libre Office and other standalone text-processors.