One of the most common “have you ever noticed” things people like to make mention of in English pronunciation – especially North American English pronunciation – is how, in many words, such as matter and betting, “we say ‘t’ as ‘d’.”
I put that in quotes because that’s what people say.
It’s not really true.
Actually, we say them both as a third sound. It just happens that this third sound, to our ears, sounds more like [d] than like [t]. (By the way: I’m using the linguistic standard of putting a sound in brackets, [t], if it’s the sound we’re actually making, and between slashes, /t/, if it’s the sound we believe ourselves to be making whether or not we actually are making exactly that sound. So “hit it” will always be /hɪt ɪt/ but not always [hɪt ɪt].)
Here, I’ll prove that we don’t say it as [d]. Say the following, slowly and carefully, perhaps as though you’re speaking to someone who is hard of hearing:
I’m not kidding about the reckless betting.
No problem making /t/ and /d/ different there, right?
Now say it quickly, as quickly as you reasonably can, maybe two or three times in a row.
Those d’s and t’s seem to be pretty much the same sound now, right? All d’s, perhaps?
No, not all d’s. Say this slowly and carefully, perhaps as to someone who is having a hard time hearing you:
I’m not kidding about the reckless bedding.
Before, when you said “reckless betting” quickly, there was no problem with a hearer knowing you were talking about gambling. But when you say the [d] clearly, that’s out the window; you’re now talking about crazy quilts and sheets. You can’t say “bedding” clearly and be taken for saying “betting” under normal circumstances.
We tend to think that we’re saying it as [d] because most of us don’t have a letter to associate with what we are saying it as. But I’ll tell you what we’re really saying it as: a thing linguists call a tap. The tongue just taps the alveolar ridge without really stopping the airflow. We sometimes make a flap, which is when the tongue taps on the way past rather than bouncing off. A tap is like in “better” (said quickly and casually); a flap is like in “editing” (said quickly and casually). The International Phonetic Alphabet symbol for a tap or a flap is [ɾ].
Does that look like a partly-formed r? As well it might. Some speakers – particularly those with accents we might think of as “proper” British – will use it for /r/ in the middle of words, as in “very horrifying.” North Americans, who aren’t used to saying /r/ that way, often represent this as a d as in “veddy British.” But it’s not [d]. It’s [ɾ].
Here’s how sounds work in language: Every language has a set of sounds that are considered to be distinctive – swap in a different one and you have a different word (or a non-existent word). These distinctive sounds are called phonemes. Do not confuse these with the letters of the alphabet. For instance, c is a letter that can stand for the phoneme /k/ as in can, /s/ as in ice, or even /tʃ/ in some loan words such as ciao. On the other hand, /k/ is a phoneme that can be represented by c as in can, k as in kill, ck as in kick, ch as in school, q as in question, even que as in unique.
But a sound that is considered to be distinctive may have several different ways of being produced, depending on where it shows up. We just happen to hear them all as versions of the same sound and thus interpret them all as the same sound by habit without generally noticing that there is any difference. Take /t/, for instance. Say the following words:
ting sting matting mattress mat mitten
Each one has a different version of that /t/. Linguists call these different versions phones (as if that word didn’t have enough meanings already). The system of phones is phonetics, while the system of phonemes is phonemics. (Phonics is not a word linguists use.)
Put your hand in front of your mouth and say “ting sting.” You might feel an extra puff of breath on “ting.” If you say “pill spill” you will feel much more of a puff on “pill.” We put those puffs on voiceless stops (/k, t, p/) when they’re at the very beginning of a syllable – but not if there’s /s/ before them at the start of the syllable. Those puffs are called aspiration.
That’s two of the six different variations on /t/ – what linguists call allophones of /t/. I’m sure you can hear the different allophones in “matting” (with the tap) and “mattress” (with “mattress” the /tr/ together sound like “ch” plus “r”). Now how about “mat”? The difference with that one is that we don’t release /t/ when there isn’t another vowel or liquid after it – we just hold it closed. Usually we just close our throat (glottal stop) and sometimes we don’t even entirely touch the tongue to the roof of the mouth. If you have /n/ after it, as in “mitten,” just the nasal passage releases, unless you’re speaking carefully or formally.
All of these are thought of as /t/. All of them are heard as /t/. But they really do differ. In some languages some of them are treated as distinct sounds. You know how speakers of some languages can’t say “beat” and “bit” differently? That’s because those two vowels are allophones – different phone realizations – of the same phoneme in those languages. Well, we’re like that with things like the difference between aspirated and unaspirated stops.
Why do we do this? Economy of effort. A /t/ is a voiceless alveolar stop. We don’t always retain all those characteristics of voice (voiceless), place (alveolar), and manner (stop); we’ll stick with whichever is sufficient to make the sound recognizable while not having to make too much effort to say it, and sometimes we’ll add a little more distinction where needed. So at the start of a word, we add that puff of air to make it clearer that it’s not /d/. We don’t need to do that after /s/ because we never say /sd/ at the start of a word. In the middle of a word like matter, we just keep the place and a similar manner, but we don’t stick too closely to the voicelessness or the hard stop. At the end, as in “mat,” or before a nasal, as in “mitten,” we reduce it to a different stop (glottal) that takes less effort to say. That’s also what some people (notably some British people) do when they use a glottal stop between two vowels, as though “matter” were “ma’er” (or “ma’ah”). The quality of being a voiceless stop is enough; the other two voiceless stops (/k, p/) don’t reduce to a glottal stop in English.
So those are the allophones of /t/. What you need to know is that sometimes two different phonemes have, in some contexts, the same phone as an allophone. Most “short” vowels in English reduce to a neutral unstressed vowel [ə], for instance. The case in point today is [ɾ], which can be a version of /t/ or /d/ (or, in some kinds of English, /r/).
We think of voice as the difference between /t/ and /d/. But they’re stops – how do you voice a consonant when your air flow is stopped? You don’t, really. You know the difference between /t/ and /d/ mainly by how the sounds before and after behave. Say this:
mad mat
In “mad” your voice keeps going right up until you say the [d], but in “mat” you cut off a moment sooner. You also say the vowel a bit shorter.
Now say this:
The madder matter
The difference is very subtle, isn’t it? But you may say the [æ] before the /d/ a little longer than before the /t/, and you may cut the voice out just a little for the /t/ version. It’s not really enough to be sure about when you’re listening, but there may be that small effect of the sound you’re thinking about when you say it.
On the other hand, you might really say them both the same way.
It just happens that that way will not be with [d]. It will be with [ɾ].
Sesquiotica 