There are people among us who feel insulted or personally threatened when they hear someone speaking Spanish instead of English on our American streets.

It doesn’t matter if the person that they've overheard comes from Mexico or Spain, or how or why they arrived here, or what kind of person they are -- their spoken language is experienced as an irritating personal affront to quite a number of us.

I have seen it happen twice in the last month, and I often wondered at the mindset that responds like this. Spanish is the second-most widely spoken language in the world (after Mandarin Chinese) with an estimated 400 million native speakers and an official status in 21 countries, including South, Central and North America, as well as Africa and Europe.

Here in the U.S. it is estimated there are 30 to 40 million native Spanish speakers.  Statistically that means you are very likely to encounter it.

So to dramatically purse your lips, to look as though you’ve discovered a foul odor, to complain bitterly because you’re suddenly overhearing it, to consider it as a foundational threat to your politics or your values seems a little ridiculous to me.

Most people who speak Spanish here can also speak English, but the same is far less true the other way around. It’s what we don’t know that seems to unsettle some of us. Our discomfort can be rooted in ignorance.

And be assured, it is ignorance. Every language on Earth is a repository of expression and experience, reflecting the unique cultures of those who speak it. It’s the gateway to a new world and an expansion of what it means to be human. 

That’s why learning a new language literally increases the size of your brain.  Swedish scientists discovered this in 2012 when they used brain scans to monitor what happens when someone learns a second language.

When we learn a new language, we create new neural pathways in our brains. Learning a foreign language can result in the thickening of the cerebral cortex, a layer of neurons specifically responsible for memory, thought, consciousness and language.

This increased thickness is believed to improve our memory and critical thinking later in life. It’s a win-win, as they say.

But learning a new language doesn't just rewire and renew our brains. It can also change the way we relate to other people and expand our perception, changing how see the world.

So the people who grouse when they hear Spanish or any other language spoken in America are already huddled in a defensive crouch. They stand at the entrance to a greater understanding of what it means to be human, and they slam the door shut.

If you experience human diversity as a coded threat to your way of life, rather than what it actually is, simple human variety, then very little will dislodge your deep seated fears.

I have seen many Americans fall down this rabbit hole of anxiety and rejection more times than I can count by now.  They divide the country into columns. For people like this the only way to win is for others to clearly lose.

For them the nation must exclusively reflect all of their values, or else it is not their nation. People must always behave and speak the way they expect them to or else they will feel alienated and excluded. 

There are two ways to respond to human diversity, history teaches us. You can try to smash the culture, language and aspirations of your neighbors to pull them into your orbit and sphere of control, or you can grow alongside them, transforming yourself and your own perceptions in the process. One route is very much more rewarding than the other.

Being Irish, we know all about forced attempts to make us conform and speak English, or we should.

We know that it’s about more than just standardizing the language. We have learned from history what happens when a dominant culture tries to rob us of what makes us unique.

That’s why I instinctively bristle every time I see someone make a face at a Spanish speaker on the city streets. I realize that their response to simple human diversity is a barely concealed desire to smash it. I have seen where that leads at home, and I wouldn’t wish it on anyone.

New York City subway: "Being Irish, we know all about forced attempts to make us conform and speak English, or we should."iStock