1. Computer Skills

Quick Tip: Bulk Add Words to Your Mac's Spell Check Dictionary

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The OS X built-in spell check is great, but it is not complete. It often does not include technical terms or brand names. If you routinely use words that your Mac’s dictionary doesn’t contain, and don't want the hassle of adding them one at a time, it might be worth your while bulk adding a list of words. In this tutorial I’ll show you how to do just that.

Accessing Your Mac’s Dictionary File

Your Mac stores its spell check dictionary file in a hidden folder. The easiest way to access it is to use Terminal.

Tip: OS X Lion, Mountain Lion and Mavericks hide the ~/Library folder by default. To understand different ways that this folder can be accessed, refer to the Tuts+ tutorial How to Reveal Your Library Folder in Lion or Mountain Lion. The instructions given also work with OS X Mavericks.

  • Navigate to the Applications folder and open Terminal.
  • Enter open ~/Library/Spelling/ and press Return.
  • This will open a Finder window. The file LocalDictionary contains the dictionary your Mac uses for spell checking.
The location of LocalDictionaryThe location of LocalDictionaryThe location of LocalDictionary
The location of LocalDictionary
  • Option-Drag the LocalDictionary file to your desktop to create a backup copy. It is not strictly necessary but it is good practice to do so anytime you are editing any of your Mac’s system files.
  • Double-Click on LocalDictionary to open it in TextEdit.
My original LocalDictionary fileMy original LocalDictionary fileMy original LocalDictionary file
My original LocalDictionary file

Adding Words to the Dictionary File

The words in the dictionary file are arranged alphabetically. When your Mac scans to see if the dictionary contains a word, it stops once it reaches the point where it should be. In other words, if you put the word colour at the end of the dictionary, it will not be detected because spell check will only look up to theCs.

Similarly, if you put the word Zebedee at the start of your list, spell check would stop instantly. When you are adding words to the dictionary you must be careful to keep them in alphabetical order.

  • Create the list of words that you want to add to the spell check dictionary. I am using a list of camera equipment manufacturers.
My list of camera equipment manufacturersMy list of camera equipment manufacturersMy list of camera equipment manufacturers
My list of camera equipment manufacturers
  • Unless you want to overwrite your dictionary, you need to merge this new list with the current one. One way is to do it manually and just copy and paste the words into the correct spot in the list. Alternatively you can use a service like The Alphebatizer.
  • Copy and paste both word lists into The Alphabetizer. Select Newline under Separate Terms With: in the bottom left. Click Alphabetize to sort the lists together.
Alphabetising the list using The AlphebatizerAlphabetising the list using The AlphebatizerAlphabetising the list using The Alphebatizer
Alphabetising the list using The Alphebatizer
  • Copy and paste the new merged list into the LocalDictionary file and save it.
The merged listThe merged listThe merged list
The merged list
  • Open Terminal and enter the command killall AppleSpell and press Return to restart spell check.


Now your Mac's spell check will include all the words you've added to the list. Not only is this technique great for adding a load of words to your spell check dictionary, it can also be used to copy across your spell check when you move computers.

Instead of your Mac having to learn all your friends' names again, you can simply copy the contents of the LocalDictionary file and email it to your new Mac. Have you any lists of words you'd suggest adding to your Mac's dictionary? Let me know in the comments.

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