So let’s talk about last week’s episode. This is our first two-parter, so you might
want to go back to our one on phonemes before you jump into this one. Phonemes are
the basic sounds of language, the building blocks we use when we want to make our words. With
phonemes, we know how much variation we can take before we move into a different sound. But not
all variation is random; sometimes, we can predict it, and know what changes we can expect
see in the world. I’m Moti Lieberman, and this is the Ling Space.
So let’s start off with the mystery that we introduced at the end of last episode. When an English
speaker hears a sentence like “Let’s scoop this goop,” they hear the /k/ in “scoop”
and the /g/ in “goop” as different sounds. But if we just take a second here and listen
to them by themselves without the s, the /k/ and /g/ actually sound the same: “goop”,
“goop”. Why does it sound so different when you stick the s in there? Why’s our
brain taking in the same sound, but then interpreting it as two different phonemes, /k/ and /g/?
Before we can answer that, we have to go back to talk again about variation. Some of the variation
that we have in speech is just because we’re not perfect robots that do the same thing
every time - our tongues don’t just click into place. But some of it is rule-driven -
a given phoneme will show up differently depending on what it’s pronounced near.
So /t/ will be pronounced like [tʰ] at the beginning of a stressed syllable, like
in [tʰim], but as a flat [t] if it’s not quite at the beginning, like in [stɑɹt],
or a flappy sound like [ɾ] if it's between a stressed and unstressed vowel, like in [bʌɾɚ].
And that’s not even the end of it – there are a lot more varieties of /t/. Each of these
versions of /t/ that comes up in some given environment is known as an allophone of /t/.
Now, you’ve probably never noticed this variation before; in fact, you might
even be having trouble hearing the difference between these sounds now that we’re talking about them.
That’s totally normal! Like we mentioned last week, humans are really bad at telling
the difference between two sounds that are part of the same category - think about that experiment
we mentioned last time, telling us that our brains can't even tell the difference between
one version of [ta] and another, slightly different version of [ta]; it’s only if the difference tips over into another
category, like [da], that it matters.
And the point is all these allophones are part of the same category! All those different
[t]'s are just different flavors of the same underlying /t/ phoneme. They never cause
the meaning to change in English - saying [stʰoɹm] instead of [stoɹm] might sound
a bit weird, but you don't think, well, I just heard some word I've never heard
before in my life. I wonder what it means. You just think, hey, Moti said storm funny. Haha!
Knowing which allophone should show up in what environment is important
for a lot of linguistic research. So linguists use what’s known as a distribution statement
to easily tell at a glance what the underlying phoneme is. It also tells you what variation we can find,
depending on what you’re pronouncing the sound near. So let’s look at /t/. We’re going
to need some non-English symbols here for now, but don’t worry - we’ll cover them
in a future episode. If we have this /t/ here, that means it’s the phoneme, the mother
that controls all the little sounds below.
And underneath, we draw little lines that go to the different allophones, and say when
those show up: [tʰ] when it’s at the start of a stressed syllable,
[ɾ] when it’s between a stressed and an unstressed vowel, etc. We could fill in all those other
rules that lead to the allophones of the big mother phoneme /t/ below, too. And after
we list all of the other possibilities that are dependent on context, we also need to
remember to add another sound that’s the same as the phoneme itself, so, another [t].
That’s what you put in whenever the other rules don't apply; it shows up elsewhere, where the other
allophones fear to tread. Finding the allophone with the elsewhere distribution shows
us what the basic underlying phoneme is. So that’s how we know we need the /t/ up
top there.
Oh, and here’s a weird fact about phonemes, by the way. Phonemes are totally just a thing
that exists inside your head. By definition, anything you ever hear is always, always
just an allophone, like, even if there isn't any variation. Like with /s/ in English, there’s only one allophone, [s].
So you get a sort of stupid rule - whenever there’s an /s/, you pronounce it
like [s] - but you still do it. It's a totally unconscious process. Phonemes are just little
abstract categories that exist in your mind. They say, this range of sound waves should be interpreted
this way when you want to take these sounds and turn them into language.
But phonemes only exist in your mind, like little mental unicorns. What escapes out into
the world from your mouth and bangs into other people's eardrums are always the allophones that are
produced from a given phoneme.
That means when we hear someone talking to us, we have to take the sounds that we hear and turn them
back into the mental categories that matter for words. We have to take the allophones that we hear
and quickly turn them back into the phonemes that they came from. Let’s go back to our mysterious
sentence: “Let’s scoop this goop.” In “scoop”, the phoneme for the second sound
is a /k/. But when you slice off the [s] and listen again, it totally sounds like a [g].
This is because [g] is an allophone of /k/, that appears after an [s]. That’s a rule that happens
all over English. But because it happens all the time, our brains know that that really should be a
/k/ there. The [g] which is an allophone of /k/ never gets confused for the [g] that's its
own phoneme, like in “goop”. That's because the /k/ version is completely predictable from
the sounds around it. And that’s what allophony is: totally predictable patterns
of sound variation, that people basically don’t notice and that don’t change the
meaning of words.
And same as phonemes, the allophones that a language has can be really different, too. Like, say,
[l] and [ɹ] do exist in Korean, contrary to what you might have heard; it's just they're
both allophones of the same phoneme /l/. English has aspiration, that puff of air that comes at the beginning
of a word like “port”, but French doesn’t – in French, the [p] in “port” and in
“sport” are the same. Or in Japanese, you don’t get [t] before [i] natively, only
in front of other vowels. Instead, you get [tʃi]. And so my name gets changed to [motʃi]
by a lot of older Japanese speakers. Which means rice cake. I’m not a rice cake!
So every language carves up the space differently. The same sounds can mean a lot or nothing
at all depending on what language background you’re from. Speakers of different languages follow different
rules, and hear different sounds. Your whole experience of speech sounds is different depending
on what your native language is. Phonemes and the rules that turns them into allophones
define how you hear and understand your linguistic world. So at least now, you’ve been introduced to
your acoustic overlords.
We’ve reached the end of the Ling Space for this week, but if you rode the mental
unicorns all the way to the end, you learned that a lot of the variation that we hear in speech
isn’t just random, but is instead covered by rules; that allophones are the sounds that get produced
by applying those rules to phonemes; that we don’t ever hear the phonemes themselves, but instead just
the allophones; and just like different languages have different phonemes, they all
have different rules for making allophones.
The Ling Space is written and produced by me, Moti Lieberman. It’s directed by Adèle-Elise
Prévost, our production assistant is Georges Coulombe, and our music and sound design is by
Shane Turner. Our educational consultants are Level-Up Learning Solutions, and our graphics
team is AtelierMuse. We’re down in the comments below, or you can bring the discussion over
to our website, where we have some extra material about this topic. Check us out on Twitter, Facebook and
Tumblr, and if you want to keep expanding your own personal Ling Space, please subscribe.
And we’ll see you next Wednesday. Arrivederci!