Researchers analysing several centuries of literature have spotted a strange trend in our language patterns: the words we use tend to fall in and out of favour in a cycle that lasts around 14 years.

Scientists ran computer scripts to track patterns stretching back to the year 1700 through the Google Ngram Viewer database, which monitors language use across more than 4.5 million digitised books. In doing so, they identified a strange oscillation across 5,630 common nouns.

The team says the discovery not only shows how writers and the population at large use words to express themselves - it also affects the topics we choose to discuss.

"It's very difficult to imagine a random phenomenon that will give you this pattern," Marcelo Montemurro from the University of Manchester in the UK told Sophia Chen at New Scientist.

"Assuming these patterns reflect some cultural dynamics, I hope this develops into better understanding of why we change the topics we discuss," he added. "We might learn why writers get tired of the same thing and choose something new."

The 14-year pattern of words coming into and out of widespread use was surprisingly consistent, although the researchers found that in recent years the cycles have begun to get longer by a year or two. The cycles are also more pronounced when it comes to certain words.

What's interesting is how related words seem to rise and fall together in usage. For example, royalty-related words like "king", "queen", and "prince" appear to be on the crest of a usage wave, which means they could soon fall out of favour.

By contrast, a number of scientific terms, including "astronomer", "mathematician", and "eclipse" could soon be on the rebound, having dropped in usage recently.

According to the analysis, the same phenomenon happens with verbs as well, though not to the same extent as with nouns, and the academics found similar 14-year patterns in French, German, Italian, Russian, and Spanish, so this isn't exclusive to English.

The study suggests that words get a certain momentum, causing more and more people to use them, before reaching a saturation point, where writers start looking for alternatives.

Montemurro and fellow researcher Damián Zanette from the National Council for Scientific and Technical Research in Argentina aren't sure what's causing this, although they're willing to make some guesses.

"We expect that this behaviour is related to changes in the cultural environment that, in turn, stir the thematic focus of the writers represented in the Google database," the researchers write in their paper.

"It's fascinating to look for cultural factors that might affect this, but we also expect certain periodicities from random fluctuations," biological scientist Mark Pagel, from the University of Reading in the UK, who wasn't involved in the research, told New Scientist.

"Now and then, a word like 'apple' is going to be written more, and its popularity will go up," he added. "But then it'll fall back to a long-term average."

It's clear that language is constantly evolving over time, but a resource like the Google Ngram Viewer gives scientists unprecedented access to word use and language trends across the centuries, at least as far as the written word goes.

You can try it out for yourself, and search for any word's popularity over time.

But if there are certain nouns you're fond of, make the most of them, because they might not be in common use for much longer.

The findings have been published in Palgrave Communications.