Tired of annoying “red dots” under every single word because your language is not supported by OS X spell‑checker? Here's what to do to completely disable it. System‑wide & for ever.
To disable SpellChecker you need to rename folder containing its resource files. Simply open Terminal and write down:
cd /System/Library/Services/AppleSpell.service/Contents/ sudo mv Resources Resources_DISABLED
Original source of solution: http://www.chromescreen.com/disable-spell-checker-in-mac-osx-system-wide/
Original source of solution: https://discussions.apple.com/thread/2577594?tstart=0