NOTE: You will need access to System and Configuration to make changes.
Go to System and Configuration
In the Configuration tab choose Workstation tab and Configuration again
Choose Spelling options and make any amendments. Click OK and Save
There are two additional tabs where additions or amendments can be made:
User Dictionary Contents is where additions that have been made to the Dictionary are stored. If errors have been made they can be amended here
Common Misspellings are where you could add things that you constantly misspell. For example, I commonly mistype the word 'Property' as 'Proerpty' and could add this to my Common Misspellings and it would save me from my poor typing!