Misspelled is a chat spell-checker addon. Misspelled watches the chat messages you type, highlighting any misspellings and offering suggestions for any misspelled words it finds.

I've included in the US & UK English dictionaries some Warcraft specific proper nouns, including the zone names, and all dungeon and raid boss names. Your friends and guild members are also automatically added and shouldn't get flagged as misspelled words. Misspelled utilizes the HunSpell style, affix (prefix/suffix) compressed dictionaries. The same ones used in Chrome, Firefox, and OpenOffice. Misspelled provides suggestions based on words that phonetically sound like the misspelled word, along with providing suggestions based on common mistakes of spelling. While Misspelled can detect nearly the same number of individually correctly spelled words as OpenOffice, it's suggestion engine, is "somewhat" less complicated, than the HunSpell implementation.

Misspelled includes dictionaries for US-English, UK-English, French, German, Italian, Russian (experimental), and Spanish. The appropriate dictionary, for your game client locale, will auto-load, or you can manually choose what dictionary to use from Misspelled's Interface/Addons options page.

Misspelled works with WIM (Wow Instant Messenger), and is compatible with: Prat, Skinner, and Chatter.

Usage note: Spell Checking is performed as you complete each word you've typed. The last word in the chat box, isn't spell checked until you type some form of word terminator, either a period, space, or some other word separating punctuation. Spell checking is very fast; but isn't performed needlessly, while a word is being typed.

Misspelled is compatible with WoW, WoW Classic and Wow Classic BTC If you are having problems with Misspelled, please try updating or disabling all other chat addons you may be running.

Distribution Points
Curseforge: https://www.curseforge.com/wow/addons/misspelled
WowInterface: https://www.wowinterface.com/downloads/info13493-Misspelled.html