Basically, Google Ngrams searches all of the 5.2 million books digitized by Google for whatever word(s) or phrase(s) you want to look for or compare. It then plots them on a graph. This is extremely useful when proofreading as it helps me to choose between variant spellings, particularly if an author has used more than one in their work.
Have a look at this example:
Charts like the one below also show which version of a phrase was in common use in a particular era. You can even use it to check whether a word you’re considering using in your period piece was in common usage at that time.
In general, it’s rather interesting to see how words or phrases have risen or fallen in popularity. Here’s the trajectory of ‘twerk’:
You can also search in many languages, including British or American English, and choose a shorter time span. It can even be used to explore cultural change and the popularity of ideas.
It’s a handy and rather interesting tool. Click here to have a go.
What do you think? Have you used it in your editing?