Can I disable auto-correction of a single word on OS X?

I'm running into an annoying issue with OS X's automatic spelling correction where the word nala gets automatically corrected to napa.

I've tried adding nala to my custom dictionary under ~/Library/Spelling/LocalDictionary but it still reliably makes the correction anyway.

How do I configure OS X to not automatically correct a given word short of turning off automatic correction entirely which is not really desirable?

Yes you can do it.

1. Go to System Preferences > Keyboard > Text.
2. Click the + sign on the bottom left to add a new text replacement.
3. In the Replace column, put the word you want OS X to stop autocorrecting (no spaces are allowed).
4. In the With column, put the exact same word you put in the Replace column.

Voila. You're done.

This has worked flawlessly for me every time.

When typing the word, right-click it and choose Spelling & Grammar → Show Spelling and Grammar. This will bring up a window similar to the one below. It should say that the word was not found in the spelling dictionary.

Click Learn to teach the word to the current dictionary.

The file ~/Library/Spelling/LocalDictionary only contains some of your corrections. This depends on which language you have currently selected. For example, my ~/Library/Spelling/ folder contains multiple custom dictionaries depending on the language that I have currently set. As well as LocalDictionary, I have files named en and en_GB. Editing these files instead of LocalDictionary can help set custom words when they refuse to be read from LocalDictionary.

~/Library/Spelling
├── LocalDictionary
├── dynamic-counts.dat
├── dynamic-text.dat
├── en
└── en_GB 
0 directories, 5 files