This article is based on a posting that appears on SolidWorks Legion.
SolidWorks has a spell checker? Yup! It’s called Spelling Check and can be invoked on most installs by pressing F7 or by going to Tools>Spelling.... Spelling Check can be useful when proofreading a drawing. You can customize Spelling check by adding more words to its dictionaries. There're several ways to add words to the Spelling Check.
Run Spelling Check on a drawing which includes new words within annotations. When Spelling Check identifies a new word as a misspelling, simply click the Add button in the PropertyManager. This method creates and modifies a file called swdictionary.dic, located in the SolidWorks folder under \lang\english (or the installation language). The file does not exist until you add your first word.
If you wish to update Spelling Check with a bit more control (adding and deleting words), start Spelling Check and choose the More Options... button in the PropertyManager. On the Spelling Options dialog, choose Dictionaries button. Highlight "swengineering" then choose the Edit button. OK, now that you've made it here, add and delete words one at a time. This method will edit your swengineering.dic file (same location as the swdictionary.dic file). The limitation is that you cannot delete any already existing words. You can only delete the words that you add.
In my opinion, the easiest way to add words to Spelling Check in bulk is by editing your swdictionary.dic file directly with Notepad. With the file open, add one new word per line. Use all capital letters. Capital letters are not a requirement. It will simply keep the dictionary listings consistent within the file, especially if other words are added later by using Spelling Check.
As with other similar types of SolidWorks resource files, the swdictinoary.dic and swengineering.dic files can be located on a network drive for standardization across an enterprize. Presumably, these files should be in the same folder. To set the file location, goto Tools>Options...>File Locations and select Spelling Folder. New dictionary files can also be added within Spelling Check's Dictionary window.