Hi Alison

You are right!

Here's the paragraph from the essay "Do We Need So Many Languages?"

In conclusion, our native language is one way of expressing our ideas and worldview. If it’s useful, we should use it, but we should also realize that our identity and potential is not limited to the geographical accident of our birthplace and native language. What’s more important is that we learn to think, reflect, and genuinely communicate with others, regardless of what languages we use.

I'd probably change it to:

In conclusion, our native language is one way of expressing our ideas and worldview. If it’s useful, we should use it, but we should also realize that our identity and potential are not limited to the geographical accident of our birthplace and native language. What’s more important is that we learn to think, reflect, and genuinely communicate with others, regardless of what languages we use.

If we wanted, we could change all the words to their plurals: identity to "identities", "potential" to "potentials", "accident" to "accidents," "birthplace" to "birthplaces",  "native languages", and so on.

But I don't think there's really a grammatical need to do it. The singular version is clearer and simpler, and the plural is understood.

Thanks for reading the essay and for being so eagle-eyed!