You keep using that word. I do not think

[rivka]

This speaker obviously knew the word criterion. But most native speakers, who have had as much experience as you can get, don't use criterion as the singular. Hence my claim that being a native or non-native speaker has nothing to do with this.

There is a huge difference between using "criteria" as both single and plural (as most native speakers do), and the over-correction of using "criterion" as a plural. I still think the latter is far more likely from someone who did not grow up hearing the language spoken.

[Porter]

This speaker obviously knew the word criterion.

The speaker knew of that word, but obviously didn't really know it, or they wouldn't have used it as the plural of criteria.

[Jonathon]

It is not a Greek plural. It is a Latin one.

It may have been borrowed into Latin, but it kept its Greek declension.

link

If it had been Latin, it would have been criterium/criteria, as far as I can tell.

[goofy]

This speaker obviously knew the word criterion. But most native speakers, who have had as much experience as you can get, don't use criterion as the singular. Hence my claim that being a native or non-native speaker has nothing to do with this.

There is a huge difference between using "criteria" as both single and plural (as most native speakers do), and the over-correction of using "criterion" as a plural. I still think the latter is far more likely from someone who did not grow up hearing the language spoken.

But... it's the only word in English that can follow that pattern. Growing up hearing the language spoken isn't going to help, because there are no other words that form their plural like this. And anyway, most speakers don't use criterion at all. We learn about criterion/criteria by reading about it in a usage book or dictionary, which non-native speakers can do as easily as native speakers. I believe you that you learned it in primary school, but I'm claiming that that is the exception.

[Jonathon]

I'm rather surprised that you learned that in primary school. To be clear, we're talking about K–6, right?

Goofy: Are you sure that's the only word in English following that pattern? I have a feeling that there have got to be others, but I can't come up with anything.

[goofy]

No, I thought of another: phenomenon/phenomena. There might be others. But there is a significant difference: phenomenon/phenomena have secondary stress on the last syllable, and criterion/criteria don't, so the connection is not transparent.

[Porter]

We learn about criterion/criteria by reading about it in a usage book or dictionary, which non-native speakers can do as easily as native speakers.

Not me.  I learned learned about criterion/criteria by hearing it used.  Essentially by growing up hearing the language spoken.  Probably from a book, but I have no memory of it.

If I were not a native speaker, there is a lower chance that I'd know that word, as I would have had less experience in the language to pick it up in.
 

[Porter]

Medium/media is almost the same.

[rivka]

I'm rather surprised that you learned that in primary school. To be clear, we're talking about K–6, right?

Fairly certain the year we had a whole section on Greek/Latin roots and stuff was 6th grade. Wouldn't swear to it in a court of law.

[Jonathon]

Porter: Right. That's the Latin equivalent of that Greek declension. And though many people are probably familiar with those forms, that might not translate into an understanding of the Greek form.

Rivka: Now that you mention it, I think I might've had something similar.  

[pooka]

Medium/media is Latin and not Greek.  But I'd be surprised if most people realized they are singular and plural of the same word.  

Maybe I'll name the space station in my book cafeterion.  

[goofy]

If I were not a native speaker, there is a lower chance that I'd know that word, as I would have had less experience in the language to pick it up in.

I'm inclined to disagree, but it's an empirical question. Where's the research on this important issue!

[Porter]

How can you disagree?  I picked it up just by using and hearing the language.   The less I had used and heard English in my life, the less chance I would have had to pick up on that word.

[Jonathon]

Psh. That's just an anecdote and speculation. We need data, man!

[Porter]

But it's the anecdote that he disagreed with!

[goofy]

How can you disagree?  I picked it up just by using and hearing the language.   The less I had used and heard English in my life, the less chance I would have had to pick up on that word.

I was going to say: because most native speakers use criteria as a singular count noun. If native speakers do it, why not non-native speakers?

But actually I'm wrong about that: altho it's common in speech and print, it's still a minority use

I don't dispute the anecdote, I just disagreed with the interpretation.

[Jonathon]

MWDEU is on Google Books? That made my day.

[goofy]

Yes! But some of the pages are badly scanned.