(upbeat music) - This episode of Other Words was brought to you by the letter R. Wait, which R are we talking about?

The English alveolar approximant, the Spanish trill, the French uvular fricative?

Or maybe we're talking about the vowel R. That's right.

There's a good argument that R is at least sometimes, a vowel.

Does that mean that your first grade teacher was lying to you?

Not exactly.

R is an incredibly weird letter with so many different sounds and functions.

It's a wonder that we use one symbol to represent them all.

And how people pronounce that one letter can speak volumes about their history, and social background.

You probably don't think much about R, when you're talking, but if there's one thing we language nerds love to do it's find the strange stories beneath our ordinary unconscious behaviors.

I'm Dr. Erica Brozovsky, and this is Other Words.

(upbeat intro) - Other words.

- As a child, you were probably just told to memorize that the vowels were A E I O U, and sometimes Y.

But linguists define vowels not so much as letters but sounds.

English has around 20 vowel phonemes like ee, ih, eh, aa, ay, ah, aw, oh, uh, and ooh.

To qualify as a vowel, a sound must meet a few general criteria.

First, it must be voiced, meaning your voice box vibrates when you make it.

Phonemes like ss, sh and h, are voiceless, they're breath only.

Second, it should function as the nucleus or peak of a syllable.

The central sound that gives a syllable its length and volume.

It's the sound you'd sustain, if you were singing the word.

♪ And I-i-i ♪ ♪ Will always love you ♪ And third, it must be produced with an unobstructed vocal tract.

What the heck does that mean?

Your vocal tract is basically the entire mechanism that shapes sounds from your vocal cord to your nasal cavity.

The different moving parts are known as articulators, and the main ones are the tongue, upper lip, lower lip, upper teeth, alveolar ridge, hard palate, soft palate, uvula, the pharyngeal wall, and the glottis.

Vowel sounds are made by contorting these articulators into different shapes, like pursing the lips for u, or flattening the tongue for a, however if any of these articulators touch each other, like pressing the tongue against the hard palate for ll, or closing your lips for mm, the vocal tract is obstructed, and the resulting phoneme is considered a consonant.

So what's going on in your mouth when you make an R sound?

Well, that depends on where you're from.

Spanish speakers will either tap the tip of the tongue to the alveolar ridge as in pero, or roll it as in perro, known as a trill.

French speakers used to trill their Rs with the tongue, but it moved to the uvula at the back of the throat, as in frere.

In English, the R sound is known as the alveolar approximant, which means the tongue flicks backwards close to the alveolar ridge, but doesn't quite touch it.

It's a tricky move to pull off and invisible from the outside, which is why it's often the hardest sound for young children to master.

What's weird is that all these different sounds made with different articulators are represented with just one symbol and considered to be part of the same phonetic family, known as rhotics.

Interestingly, English is one of very few languages, along with Mandarin Chinese, that uses the rhotic sound like a vowel, In words like bird, fur, learn, and mother, the er sound is the nucleus of the syllable.

♪ I'm like a bird ♪ - And unlike syllabic consonants, like the N in button, or the L in little, there's no direct contact between articulators, leaving the vocal tract unobstructed.

This is why many linguists believe that it meets all the criteria of a phonetic vowel.

Up to now, I've only been talking about the standard American pronunciation of R, but you're probably aware that not all English speakers say it the same way.

In fact, the pronunciation of R is one of the most vivid differentiators between English dialects.

For hundreds of years, the people of England pronounced their Rs hard, similar to how it's done today in Ireland and Scotland, but starting in the mid 18th century, it became fashionable to drop the rhoticity at the end of a word, as in stah, or before a consonant, as in paht.

At first, the trend was considered lazy, and low class, and many scholars railed against it.

Nevertheless, it spread throughout much of England, and then exported to colonies in South Africa, Australia, and New Zealand, which all now speak what are known as non-rhotic English dialects.

But because this trend began after the colonization of the new world, most North American English speakers kept their rhotic Rs, as I do today.

However, some Americans who wanted to sound proper, and upper class like the British did start adopting the R dropping trend.

It was fashionable in the US up until the early 20th century, and you can hear it in old films from the period.

- Don't miss a word.

- Today, there are still vestiges of the dropped R in cities and regions that had close contact with England, like Boston, where you park your car in Harvard yard, and New York, where you should never forget to wear your slicker.

Some New Yorkers, even up-glided the vowel R, when it proceeded a continent, as in it's my first time at the circus.

The southern aristocracy also adopted R dropping, as in I do declare, which eventually spread to most of the region, including the African-American population they had enslaved, and is today a feature of African-American English.

After the Civil War, as the power centers of America shifted westward, the traditional rhotic R became the standard once again, and the dropped R, thanks to its new association with urban areas and immigrant and black communities, reverted to a perception of a low socioeconomic status, and lack of education.

It's interesting that the pronunciation of a single letter depending on the time and place, can have such a variety of social connotations.

It's more evidence that there is no one correct way to shape a sound.

The letter R is a dramatic symbol of how language works.

It's ever changing with a beautiful range of variants, and yet, as long as we can understand each other,