America boasts more Christians than any other country on planet Earth. But you wouldn't know it from listening to us.

According to Google Ngram Viewer data, a searchable database of millions of printed works stretching back 500 years, most of the central terms in the Christian vocabulary are rapidly declining. One 2012 study in the Journal of Positive Psychology, for example, analyzed 50 moral terms associated with Christianity and found that a whopping 74 percent were used less frequently over the course of the last century:

"Grace" ... declined

"Mercy" ... declined

"Wisdom" ... declined

"Faith" ... declined

"Sacrifice" ... declined

"Honesty" ... declined

"Righteousness" ... declined

"Evil" ... declined

As David Brooks pointed out in The New York Times a few years ago, even basic moral and religious words are fading from use. For example, more general language about the virtues Christians call "the fruit of the Spirit" — love, patience, gentleness, faithfulness — has become much rarer.

The use of humility words, like modesty, fell by 52 percent over the 20th century.

Compassion words, like kindness, dropped by 56 percent.

Gratitude words, like thankfulness, declined by 49 percent.

And courage words, like bravery, plunged by 66 percent.

Ngram data is complicated and susceptible to misinterpretation, of course. The overabundance of scientific literature in the database can skew findings, for example, and it is often difficult to account for all colloquial, synonymous terms that have arisen during the same period. But the data we have cannot be dismissed out of hand, and at the very least indicates that traditional sacred speech is dying in the English-speaking world.

Now, words have fallen out of usage at every point in history. Language is always changing, and humans keep marching on. Does this trend matter?

Actually, yes. An emerging body of research now reveals that the languages we hear and speak also influence our worldviews, memories, perceptions, and behaviors more than scientists once realized. Children who grow up speaking the same words tend to think in similar ways. Our minds don't just shape our words. Our words shape our minds, too.

A linguist named Lera Boroditsky once asked an audience of celebrated scholars at Harvard University to close their eyes and point north. Hands shot up around the auditorium like roman candles, aimed in all possible directions. She repeated the experiment at Princeton and Stanford, as well as in Moscow, London, and Beijing. The result was the same — an array of hands aimed at each of the four major directions and every point in between.

But when Boroditsky traveled to a community on the western shores of Australia's Cape York, she discovered that children as young as 5 can point north at all times with absolute precision.

Why the difference? The answer, as it turns out, is words.

Many languages in the Western world use relative spatial terms. At an amusement park, you might complain that a stranger cut in "front" of you and ask them to step "behind" you. Or when unpacking boxes, you might ask someone to place your alarm clock on the "left" end table or the "right" one.

But the Aboriginal language spoken in that region of Australia — along with a third of the world's languages — use cardinal directions, which direct toward the four points on a compass, to discuss space. Someone speaking one of these languages might say something like, "My knife is southeast of my plate" or "Jackie is standing to the north of Trisha."

If we talk about north, we will think about north. If we don't, we won't.

This explains part of why the death of sacred speech should alarm the 71 percent of Americans who claim to be Christian. The less we talk about our faith, the less we will think about supernatural realities, both as individuals and as a society. God, spirituality, and the inner life will not guide our minds or influence our decision making.

There's more. Linguistic research reveals that words shape not only our thoughts, but also our behavior patterns.

As an English-speaker, I've been trained to prefer active verb constructions ("Sarah wrecked the car") instead of passive ("The car was wrecked"). If someone asks me to recount an event or recall a memory, my language has conditioned me to assign agency, even if an action was accidental. But if someone speaks a language like Japanese or Spanish, they often prefer a passive construction. Which is to say, the agent of causality is usually dropped, even if someone was at fault.

The result is that people who speak languages like English more readily blame others. Just as speaking about north conditions someone to think about north and behave with north in mind, so too does speaking about blame condition someone to think and act in corresponding ways. Linguistic research has even uncovered that, unsurprisingly, those who speak active languages like English have developed a "criminal-justice bent toward punishing transgressors rather than restituting victims."

As the language of faith has declined in usage, it should not surprise us that our collective thinking and behaviors are less dependent on spirituality than they once were. In the same way, we speak far less of grace, mercy, patience, and compassion. While we may decry that our world is not as gracious, merciful, patient, or compassionate as it might be, we must also take responsibility for the way our use of language has contributed to it.