In English, what we think of as the letter “t” is actually a collection of many different sounds – but most of the time we do not notice the difference. [1 of 2]
Why do native Japanese speakers have difficulty distinguishing “l” and “r” sounds? And why do native English speakers have difficulty distinguishing “t” and “th” sounds?
A couple of months ago – in the post on most consonants, fewest vowels – I promised to write more about phonemes, allophones, and minimal pairs. Now, this is a rare topic for me. For once I can talk with some expertise – because about twenty years ago I lectured in phonetics and phonology at a New Zealand university. It was a temporary gig and my career has gone in other directions since then, but some of the basics – Linguistics 101, if you will – still stick in my mind. Today and tomorrow I’m going to try to get them to stick in your mind.
Consider the sound represented by the letter “t” – as in “top,” “stop,” “cat,” or “winter.” In the language of the International Phonetic Alphabet, it is a voiceless alveolar plosive. This means that you make a “t” sound by putting the tip of your tongue on the roof of your mouth – near the front – building up some pressure in the air behind it, and then releasing the tongue and the air in a mild aural puff.
But here’s the thing: it’s not just one sound. Depending on its place in the word and the sounds around it, most people actually pronounce the “t” in several subtly different ways. The four words at the top of the last paragraph – “top,” “stop,” “cat,” and “winter” – are actually four different sounds. The “t” in “top” is followed by a breathy sound called aspiration. The “t” in “stop” lacks this aspiration. The “t” in “cat,” coming at the end of the word, is unreleased – that means that we build up the pressure behind the tongue but don’t release that pressure. The “t” in “winter” is nasalised, which means that air is coming through the nose as well as the mouth.
Now, it’s actually really difficult for a monolingual English speaker to tell the difference between these four sounds, and there’s a very good reason why. Switching from one sound to another does not change the meaning of the words.
I’ll repeat that, because it’s important: switching between these sounds doesn’t change the meaning of the words. I could pronounce “cat” with a released “t” sound and it would still mean the same thing. I’d sound kind of annoyed, like the cat in question had just thrown up in my shoes, but I would still be talking about a cat.
What we think of as one sound – “t” – is actually a cluster of sounds. The position of the “t” in the word determines which of those sounds is used. Does it begin a word or end a word? Does it follow an “s” or an “n”? Those questions lead us unconsciously to one sound or another. It’s not a conscious choice to use one sound or another. Instead, we’re just reacting to some hidden rules of pronunciation.
You may think that these differences are trivial. Sure, we pronounce sounds slightly different depending on their context, but why does that matter? Well, here’s the trick: the difference between those sounds doesn’t matter in English. In other languages, the difference is very important.
[Part 2 comes tomorrow.]
The Generalist Academy 
