Automated Spell Checkers
An automated spell checker can save you huge amounts of time but you must bear in mind its limitations. Modern applications like MS Word, with their graphical highlighting of misspelled words allow you to go quickly through a document and correct obvious typos before you undertake a thorough proofread. This is where many people go wrong though. They believe that because they've done the spell-check, all of the words will be spelled correctly.
What they've actually checked is that all of the words are recognised by the software dictionary, not whether they've used them in the right place or in the right context. Think about common mistakes you’ve seen in the usage of 'their' and 'there'. A spell-checker will not know if you've used the wrong one. You have to read the work to find that out.
Spell-checkers also will not help with consistency. You can easily employ different, but allowable, spellings of the same words within a document without upsetting the spell-checker. For example, you could include both 'authorize' and 'authorise' in the same document without attracting a spell-checker error, but this would be a glaring inconsistency in your work. If you are a technical writer, there should be an established style guide to tell which version you should use. If you are writing for yourself, then you need to decide which version you are going to use and stick to it. Consider having your own personal style guide to help record these decisions for future work.
The Add Button
In MS Word, the spell checking dialogue box offers the ability to add words to the dictionary using an ‘add’ button. Be very careful when you use the ‘add’ button. Always make sure you have checked the spelling of a word before you press ‘add’. Once it’s in the software dictionary, it won’t be highlighted as a mistake in the future, so you have to get it right.
Language Settings
Make sure your spell-checker is set to the correct language. This isn’t as silly as it may sound when you consider the differences between UK and American English, for example.
If you are using the wrong in-built dictionary in your software application, the spell-checker may be trying to correct spellings that are perfectly acceptable. Likewise, it will not highlight some that should be fixed.
This is particularly relevant in the UK, where many computers default to US English (or American English) when the software is installed. The installer may not have changed it to UK English for your computer. You must check.