The blue wavy line in Word can mean one of the two things. It is Contextual Spelling Errors and other one is called Formatting Inconsistencies.
Contextual Spelling Errors
It sounds complex but it is really a very useful feature. It simply checks where you have used the right word in the wrong place.
Sometimes, we make these mistakes. In the first sentence, instead of a question mark, a period was used.
In the second case, the spelling of LOOSE is right, but it is used in the wrong place – or wrong context. Technically these are called HOMONYMS – words with different spelling but same pronunciation. Regular grammar checker does not catch that mistake. But this one does.
Complex processing goes on behind the scenes
For those of you who are academically interested, you can read the research paper which led to this feature. Compressing Trigram Language Models With Golomb Coding
This feature may not be enabled
This feature is available from Office 2007 onwards. However, if your PC has less than 1 GB memory, this feature is inactive by default.
Why so? Because, this feature requires lot of processing power and memory. If your PC has less memory, it may slow down your work. That is why it is automatically disabled.
How to activate this great feature?
Office 2007 and 2010
File – Options – Proofing
Office 2013 – see what Microsoft did?
Microsoft programmers realized that people do not understand the phrase Use Contextual Spelling.
So you know what they did in Office 2013?
They just simplified the description … have a look.
That is called User Focus
Unbelievable but true.