Posted by Neal on March 18, 2010
This is another follow-up to my St. Patrick’s Day post, where I talked about how /t/ can sound like [ʧ] (“CH”) before an /r/. There’s another angle I wanted to explore, but first, I have to tell you about something else that happened in that classroom where I got pinched for not wearing green on St. Patrick’s Day.
Now that I think about it, I think it was kindergarten, not first grade. I’m remembering my kindergarten teacher, Mrs. Casas, handing me that construction-paper shamrock. Casas is a Spanish surname, which isn’t too surprising, because I lived in El Paso, Texas at the time. (When my relatives came to visit, they couldn’t wait to go across the border to visit Juarez. How times change.) A good number of my classmates were Mexican-American kids. One of them was named Dino, and I thought it was the coolest thing that he had the same name as the Flintstones’ pet. One day Mrs. Casas, was taking us through the alphabet, asking for words that began with each letter, and I could hardly wait for her to get through A, B, and C so I could offer up Dino’s name for D. The instant Mrs. Casas got to D, my hand was up.
“Dino!” I was surprised Dino hadn’t thought of it first.
“What?” Mrs. Casas asked.
“Dino!” I pointed at Dino to make sure she understood. Dino was looking at me. Mrs. Casas still wasn’t writing his name on the big tablet. What was taking her so long?
That was the day I learned that the classmate I knew as Dino was not named Dino at all. His name was Tino. I couldn’t believe it. How could his name be Tino, when for half the school year Mrs. Casas had clearly been calling him Dino?
What I didn’t realize was that Mrs. Casas was pronouncing Tino’s name with a Spanish pronunciation of /t/. But why would that cause me to hear it as a /d/? It has to do with English having two ways of pronouncing /t/, and two ways of pronouncing /d/. (Of course, there are more than two, including the [ʧ] “CH” and [ʤ] “J” pronunciations, but I’m ignoring those for now.) I mentioned in the last post that /t/ and /d/ are both made by placing the tip of the tongue behind the top front teeth, and briefly stopping the airflow out of the mouth. (This area behind the front teeth is called the alveolar ridge.) What distinguishes them is what the vocal folds are doing during and just after the tongue makes its contact.
To get an idea how this works, imagine cars approaching a toll station on a highway. A couple of the lanes are just for drivers who have purchased EZ Tag, a special barcoded sticker that allows them to drive straight through the toll station, where a computer will record their passage and charge their account accordingly. Drivers who don’t have EZ Tag have to go through the other lanes, where they have to stop and pay the attendant or put money in a machine. As soon as they’ve paid, the bar lifts and they continue. Unless, of course, they’re on a business trip, and need to get a receipt to turn in when they submit their expenses. For those drivers, there will be an interval between when they pay and when they resume driving, while they wait to get their receipt.
A moving car corresponds to the vocal folds being closed enough to vibrate when air passes through them—in other words, the voice is on. A stopped car corresponds to the vocal folds being wide open, so that air passes through them without causing vibration. Paying the toll corresponds to the tongue making contact with the alveolar ridge.
The EZ Pass driver’s actions correspond to the voice never stopping when the tongue hits the alveolar ridge (or in phonetic terms, when the articulation occurs). The phonetic symbol for this sound is [d], and indeed, this is how English speakers pronounce a /d/—sometimes. A /d/ with a vowel before it and after it, as in a duck, would be pronounced this way.
The ordinary driver who stops to pay the toll and immediately resumes driving corresponds to the voice stopping during articulation, and picking up again right away. The phonetic symbol for this sound is [t]. English speakers, however, pronounce /t/ as [t] only in certain situations, which I’ll get to a little later. Furthermore, [t] is also how English speakers usually pronounce /d/ when it doesn’t have a vowel right before it; for example, in Duck! Of course, we’re used to hearing [t] as a /d/ in this situation, but phonetically it’s still [t].
So how do English speakers actually pronounce words that begin with /t/, if they don’t pronounce them as [t]? That brings us to the driver who has to wait for a receipt. This situation corresponds to the voice stopping during articulation, and not coming back on again until about 40 milliseconds afterward. It sounds like a little “puff of air” after the /t/ sound is made, and is written [tʰ]. (This interval of voicelessness is known as aspiration. The whole topic of when the voice is on or off relative to time of articulation is known as voice onset time, or VOT.) This is how English speakers pronounce /t/ when it comes at the beginning of a stressed syllable. So when Mrs. Casas pronounced Tino as [tino], I heard it as /dino/: Dino. Once I learned Dino was really Tino, I made sure to pronounce his name with a [tʰ] at the beginning, like a real gringo would.
Now let’s come back to what I said about English speakers actually pronouncing /t/ as [t] only in certain situations. The best-known example of such a situation (and the one mentioned in all the introductory linguistics textbooks for English-speaking audiences) is when it comes after /s/, as in stop. The textbooks will usually invite the reader to hold a piece of paper vertically in front of their mouth, and say a pair of words like stop, top. The paper bends away much more when you say top, with the aspiration, than it does for stop. (The same goes for all the stop consonants, in fact. You can do the same experiment for spot, pot and scat, cat.) You can also do it with a lit candle instead of a paper. I don’t advise doing it with both a lit candle and paper at the same time.
So now, how does this relate to the “CH” pronunciation of /t/? Two posts ago, I said that I pronounced /tr/ as [ʧr], but there was an exception: when the /tr/ was part of an /str/ cluster. So now there are two rules about pronouncing /t/: as [tʰ] at the beginning of a stressed syllable, and as [ʧ] before /r/. And both rules have the same exception: when /t/ is preceded by /s/. Are the two processes actually the same? In one of the messages to the American Dialect Society in that thread I mentioned, Arnold Zwicky wrote that the [ʧ] pronunciation was “a retroflex fricative version of the aspiration on the /t/.”
It’s a cool connection, but I have a problem with it. Remember that it’s not only /t/ that gets affricated. /d/ does, too, and /d/ is never aspirated. At the beginning of a word, it will be pronounced as [t] or [d], but it still gets turned into a [ʤ]. What I think is that in an /str/ cluster, there’s a tug-of-war going on between the /s/ and the /r/. The /s/ has to be pronounced with the tongue tip near the alveolar ridge. The /r/ has to be pronounced with the tongue tip further back. In my pronunciation, /s/ wins, and the /t/ is pronounced as [t]. For other speakers, the /r/ still wins, and the [t] comes out as [ʧ]. And for a subset of these other speakers, the /r/ wins so decisively that even the /s/ is affected, turning into a [ʃ].