During her plenary lecture at the 17th International Conference on English Historical Linguistics in Zürich, Anne Curzan reminded us of the enormous influence of the grammar checker in Microsoft Word.
My first thought at hearing the checker mentioned is that it is the thing I immediately turn off when I compose a new Word document. But are those green squiggly lines merely an annoyance or has the grammar checker more sinister consequences? Concern over the great impact that Microsoft Word has on the English language is not new. Ten years ago, Tim McGee & Patricia Ericsson already called the program ‘the invisible grammarian’ when they took a critical look at its influence in English composition classes.
Because Word is on millions of desktops and Grammar Checker is turned on by default, it has many more, practically invisible, “over your shoulder” opportunities to be a grammar teacher than the typical English teacher
It is unlikely that this invasive position of the MS Word grammar checker has become less over the past ten years, in fact the opposite is rather more likely.
The limitations of the MS Word spelling and grammar checkers are well known. Sandeep Krishnamurthy at the University of Washington has shown that it is easy to hoodwink the checkers. He performed experiments using some blatenty incorrect texts which nevertheless passed the spelling or grammar check. The files are here if you want to repeat these yourself.
But what are the grammatical rules the checker uses, and where do they come from? It should be possible to find out by trawling through the program, but I haven’t been successful yet. Anne Curzan suspects that the rules are put in by the programmers themselves.
If that is the case, and no linguists or other language experts are consulted, that means that the level of expertise of the English language probably doesn’t exceed that of an American college freshman. This could mean that millions of users of MS Word have their grammar checked at this level, which is a questionable state of affairs at least.
As I mentioned, my first action on seeing the green squiggly lines is to turn off Word’s check-as-you-write features, but not everyone does. How aware have you been of this feature of MS Word? And how has the grammar checker influenced your usage of the English language? Do you, for instance, accept its suggestions if you yourself aren’t sure whether they are correct? Or do you check them with other sources?
Bridging the Unbridgeable 
In the early days of Microsoft Office, I had to demonstrate its workings to my colleagues. To test the grammar check, I wrote something like “Every year, my wife and I go to the seaside for a short holiday” and so on, with some spelling errors. This resulted in a warning that I had been using male sexist language. This feature was removed in later versions, I suppose.
Hilarious! I must admit, MS Word has created a certain pattern in my writing. The relative pronoun ‘that’ is not never preceded by a comma, whereas the word ‘which’ always is. Yes, who decided this?
@Lottie: I’m not sure who came up with such a rule, but I suspect that it may have something to do with the distribution of these two relative pronouns between restrictive and non-restrictive relative clauses, which seems to have been greatly influenced by presciptions in usage guides.
The that/which rule for nonrestrictive/restrictive relative clauses was hammered home by William Strunk Jr. (yes the one from Strunk & White!) and repeated & re-repeated by generations of American college students.