One of the most beguiling mysteries of American Horror Story: Freak Show is Kathy Bates's accent, a jagged Appalachian tootle that has upstaged ravenous scenery-chewers like Angela Bassett and Jessica Lange, as well as the show's over-the-top prosthetics.

There are many mysteries of Freak Show that can only be answered by creator Ryan Murphy and the show's inner circle of writers, producers, and directors. But this accent isn't one of those. In fact, it's something allegedly grounded in reality, which is why I talked to Kara Becker, an assistant professor of linguistics at Reed College, whose specialty is American dialects. I showed Becker a clip from Bates's introductory scene in the season's first episode and asked for her thoughts.

Alex Abad-Santos: So let's get to it. What is Kathy Bates doing? Where is her accent from?

Kara Becker: She's putting on accent, so where I think she's trying to be from is the more appropriate question to answer. I don't think she's doing the best job of the accent she's attempting, as people have seemed to note on the internet. There's some variability, and she's overdoing a couple of features. But the features she's identified are relevant to the place where I believe she's attempting to be from, which is Baltimore.

Alex Abad-Santos: You mentioned something called "features." Can you explain those?

Kara Becker: Okay so the first set of features that really jumped out to me is what I would describe as the fronting of back vowels. And those are the vowels "oooh" and "oh" — I would call them "goose" and "goat" vowels, which can help with pronunciation. So a standard American English speaker would say something like "goose", and Kathy Bates is saying something like "gewse", or the words I identified in the clip, I heard her fronting her "ooh" in a word like "foolish" and in words like "you."

Basically the way we talk about vowels in linguistics has to do with their position in the mouth, where a tongue is positioned, and the shape of our mouth when we make a vowel. So every vowel, we do something different in terms of our tongue, where it is in our mouth, and the shape of our mouth. I'm describing these vowels as back vowels, as they're sort of made with our tongue in the back of the mouth.

There's actually a very common sound change that's happening in a lot of places in the U.S. — Baltimore is one of them; the South, and the West Coast — where people are taking back vowels and pronouncing them more front in the mouth. So when I say, the fronting of back vowels, that's what I mean.

Alex Abad-Santos: What's a good example of this?

Kara Becker: The best example in her speech is actually the "o" vowel, what I'm calling the "goat" vowel. So she says not "home," but "hewm," not "folks" but "feaulks," not "hope" but "hewp" so that "o" vowel, which is traditionally produced in the back of the mouth in American English, is being produced more in the front of the mouth.

It's actually a pretty common sound change that a lot of people are doing. And Baltimore is a place where people are doing this back vowel-fronting, and that's what she's doing. And she's really accentuating these back vowels are being fronted.

Alex Abad-Santos: Is this "sound change" something that's still currently happening? How new is this change?

Kara Becker: It's pretty recent. I would say it's the last few generations. It's a current sound change, meaning that it's currently spreading throughout the United States. So it's a new sound change that's happening in American English — it probably started in the South and spread to other areas.

Alex Abad-Santos: So, why do you think people are so puzzled/shocked/intrigued/weirded out by her accent?

Kara Becker: I have a couple thoughts about why people are reacting to her accent.

The first is that she's not a native speaker of Baltimore or Philadelphia English. So she's using the "right" features, but she's not a native speaker. Like most people who are not native speakers, when they put on accents, it's not going to sound exactly right. It's not going to sound native. So she doesn't sound like a native speaker of Baltimore.

"The vowels in Philly are basically the same as the vowels in Baltimore"

If you watch The Wire, many of the people on that show also front their back vowels and use all these features that Kathy Bates is using, but because they're native speakers of that variety, most of the actors on that show sound fine to us, right? We're not going to comment on the extreme accents on a show like that, because they've cast characters that speak the variety that they're using.

She's putting on a variety of features. In doing so, she's overdoing certain things. So she's picked up that people from Baltimore front their back vowels, so she might be doing it a little too much. And she's also doing variables. There are features that she's doing where uses them in one word, but not another. She's identified the features of a Baltimore accent, and is using them, but she's using them differently than a native speaker would. And so that's probably why people are reacting to the accent the way they are.

Alex Abad-Santos: Are people not used to hearing the Baltimore accent? Is that why it sounds so foreign to them?

Kara Becker: Yeah. That's the other other thing. People might not be aware of the Baltimore accent and some of these features. It's often the case when we get someone who has what people would call a "heavy accent" — people that use high rates of some regional dialect. We often notice that because a lot of us speak less markedly when it comes to our regionality. When we hear speakers who do use heavy accents, it can be of note, whether it's a native speaker or someone who's putting the accent on.

I would also point out, perhaps, the larger television audience is not that familiar with a working-class Baltimore accent. I would say yes, that she's attempting to do a Baltimore accent, and she's partially succeeding. It's not fully successful as an accent, because it doesn't sound like a native speaker of Baltimore English would sound like. I would want to give her credit for that as a dialectologist.

Alex Abad-Santos: Where does back vowel-fronting come from? Is it a regional thing?

Kara Becker: So it's a change in the last 50 years in how we're pronouncing that vowel that we think originated in the South. It doesn't vary from region to region. Rather, different individuals from those regions are going to vary in how "front" their vowels are.

"…people who are more working class are going to have what we would call heavier accents"

For instance, younger people tend to be innovators. They tend to lead when a change is happening. So it's young people in the South and the West Coast and Baltimore that are going to have the "frontest" o's. An older person from that area, since these are new sound changes, they aren't going to have vowels that sound that front.

It's a linguistic fact of life that languages change, and so we can't always identify the cause of the change. We know our vowels are going to move around. That's something that happens to all regional varieties.

Alex Abad-Santos: You mentioned that younger people might speak differently and "front" their vowels more than older people. Does Kathy Bates's age have anything to do with her accent?

Kara Becker: So one thing I would point out, that it's not necessarily accurate that an older person who was an older person whenever this show takes place that they would sound this way [the way Bates sounds]. Accents change quickly and they change over time.

My research was based on the New York accent, right. A New Yorker who was an adult in the '40s is going to sound really different than an adult today. Some of these sound changes that I'm talking about are pretty recent, so we wouldn't expect an adult in the 1940s or '50s from Baltimore to front their back vowels as much as she's doing. That doesn't really matter much on television.

Alex Abad-Santos: Are there other factors at work too? Kathy Bates is playing a working-class character. Does class have an effect on an accent?

Kara Becker: Overall, if we have a regional variety, there will be social stratification in that regional variety such that people who are more working class are going to have what we would call heavier accents.

"She says not 'home,' but 'hewm,' not 'folks' but 'feaulks,' not 'hope' but 'hewp'"

I would describe that as they're going to use higher rates of features that are native to that region. So if in New York people say "kawfee," I'm going to expect that a working class person is going to say a lot of "kawfee" but that an upper-middle class New Yorker might not produce as extreme raised, rounded vowels, and they might not do it as often as a working class person. It's completely expected to see social stratification within a regional variety. If Kathy Bates is putting on a working-class character, it makes sense that she would use a so-called "heavy" accent to do so.

There are other features. There are things in there that aren't specific to a particular region. There are more class features. For instance she takes the "th" sound in "the" and produces "duh," and "dat" for the "that." It's not something specific to Baltimore, but something we might expect in the speech of a working class American.

Alex Abad-Santos: I had looked up something called "nasal tensing." Is there some of that going on? What is it?

Kara Becker: I heard one example of that. So, the vowel in a word like "trap", or "back" or in this clip, she said "ass"— that vowel, in some areas of the country, is split. In certain context, when it's followed by certain sounds, it sounds one way, and when it's followed by other sounds, it sounds another way.

In Baltimore, Philadelphia, and New York where we get a split of the vowel, the word "back" sounds like "back", but a word like "bag" can sound like "behg." In Philadelphia and Baltimore, a word like "ass" can sound like "eyass," and so that's the tensed vowel, that the "a" vowel being produced in a tensed way. That is a way a speaker from Philadelphia or Baltimore would produce the word "ass."

Alex Abad-Santos: Are there any other features from different dialects breaking through? Someone had mentioned Pittsburgh to me.

Kara Becker: I didn't hear a lot of other dialect features creeping in. What I heard was a lot of variability and her attempt to do more Baltimore.

Alex Abad-Santos: What is watching television and all those accents like for you?

Kara Becker: It's an interesting experience.

I would say that sometimes it's very frustrating because I wish people who make TV and movies cared more about casting actors who are able to produce accents in a native way.

A lot of people who put accents on don't do a very good job of it. There are some actors who are great at it, and I really enjoy watching actors do a wonderful version of an accent that's not native to them. Like Leonardo DiCaprio is great at accents. He does a South African accent in Blood Diamond, a Boston accent in Departed. I really enjoy watching people do good accents. But I find it frustrating watching shows where there hasn't been a lot of care in matching actors with characters who are from a particular place.

This interview has been condensed and edited for clarity.