Transcript Sound Structure - University of Pennsylvania

Phonology I
Phonemes and Simple Rules
Connecting with last week
• Remember last week: the physics of speech. And,
the idea that the consonant and vowel sounds we
make have properties that can be described in terms
of places, manners, etc.
• A striking fact: There’s a sense in which all of us are
producing physically different sounds (and hearing,
then, an infinite number of different“speech events”).
Yet no matter who says “cat”, I recognize this as the
word cat in English. How can that be?
• Answer: Speech sounds are categorized by in terms
of features; these features are the basic objects of
phonology.
Example
• Take, from the last slide, my example of cat, I.e., /kæt/.
• Taking just the first segment here, the consonant that we write
as k in the IPA
• This is what we call a voiceless velar obstruent
• In the phonology, we posit that /k/ is a complex of features;
though different features are sometimes found, something like
this:
k = [+cons, +back, +obst, -voc]
(cons = consonant; back is a place feature; obst = obstruent,
voc = voice)
• Notice, then, that /k/ differs from /g/ in terms of the voc feature:
/k/ is [-voc], /g/ is [+voc]
• A large part of the sounds system of language operates in terms
of these features
Features
• Remember that when we look at the physics
of speech, we can make very fine-grained
distinctions
• Categorizing speech sounds in terms of
features is a way of eliminating that detail, in
a way.
• So, for example, as far as phonology there is
not an infinite set of degrees between
voicelessness and being voiced
• A sound either counts as voiced, or not; I.e.,
[±voc]
Example, cont.
• Let’s take an example from English nouns. We write
plurals with -s most of the time. Notice, though, that
the plural morpheme has different pronunciations on
different nouns:
–
–
–
–
–
–
Dogs
Cats
Zebras
Churches
Lemons
Etc..
• If you listen carefully, you’ll find that it’s sometimes
/s/, sometimes /z/, and sometimes /@z/ (that’s a
schwa)
• Why is that?
The plural example
• Think of different ways the change in the plural morpheme’s
sound form can be accounted for
– In the worst case scenario, speakers would just have to
memorize which sound to use with which noun. Sometimes
there’s a lot of memorization like this in language, but this
isn’t one of those cases
– Instead, the form of the plural is correlated with the final
sound of the noun:
• /-s/: cat, clock, heap, oaf
• /-z/: reed, log, flub, drive
• /-@z/: (think about this one….)
– Try it with new nouns; Bach, glog
– Focus on the /s/ versus /z/ plurals. We don’t want to just list
the consonants they come after; e.g. we don’t want to say
“plural is pronounced /s/ after /t/, /k/, /p/, /f/”
Why not?
• We don’t want to say that because a list of
consonants like that is in some sense arbitrary: it’s
just a list. Phonology doesn’t work in terms of
arbitrary lists!
• But something systematic connects all the
consonants on the /s/ list, and all those on the /z/ list;
it’s the feature [±voc].
• So what we want to say is this:
– The /-s/ form of plural is found after C[-voc]
– The /-z/ form of plural is found after C[+voc]
• In other words: The generalization about this part of
English is stated in a way that makes reference to
distinctive features.
• Probably here we want to say that plural is “basically”
/-z/, and that it gets devoiced next to voiceless
consonants. We’ll talk about rules like this later.
Phonemes
• Features are combined into larger units to make up
what we think of as speech sounds. Among those
sounds, some are special.
• The individual, distinctive sounds of a language are
called phonemes
• We saw the different consonants and vowels that are
part of English in the last lecture
• As we discussed before, this inventory will differ to
some extent by the variety of English under
consideration
• What we’re more concerned with here is this-- why is
it that we say we have e.g. both [t] and [th] sounds in
English, but only one phoneme /t/?
The basic insight
• We saw that in some contexts, the sound we
write with t is realized as [t], and in others, as
[th] (remember this works for other voiceless
stops as well):
– till vs. still, [t] vs. [th]
• As far as the sound system of English goes,
though, the difference between unaspirated
and aspirated t’s doesn’t do any real work in
distinguishing words or morphemes from
each other
• Another way of putting this is that the
difference between[t] vs. [th] is not distinctive.
Being Distinctive
• We refer to the phonemes like /t/, /d/, etc. that are
part of English phonology as distinctive because they
make contrasts between different words
• This can be illustrated for stops by using minimal
pairs: a pair of words that differ in only one phoneme:
pill
bill
[p] vs. [b]
till
dill
[t] vs. [d]
kill
gill
[k] vs. [g]
These pairs show that voicing is distinctive for these stops
• The kind of analysis can be applied to vowels as well.
• We write the phonemes in /…./ as an indication that
these are distinctive in the phonology of the language
Differences that are not
distinctive
• We started, though, by noting that some aspects of
pronunciation are not distinctive.
– Remember: aspiration (using /p/ now)
pit vs. spit
– The former [p] is aspirated, but the [p] in the latter is not
– But: the distinction between aspirated and non-aspirated [p]
is not distinctive in English (although it is in other
languages). That is, in English there are no pairs like
[pIt] ‘hole in the ground, etc.’
[phIt] (whatever this might be)
– We see from this example that aspiration is not distinctive in
English (technically we would have to do more test that go
beyond /p/, but you get the point)
Phonemes and Allophones
• Sometimes the same phoneme is
pronounced in different ways depending on
its context
• The variants of a phoneme are called
allophones of that phoneme
• When we are talking about such distinctions,
the phoneme is in slashes /…/ and the
allophones are in square brackets […]
• The aspiration of e.g. /p/ is a case of this
type; we say that /p/ in English has the
allophones [p] and [ph]
Transcribing differences
• When we transcribe speech sounds using our
IPA notation, we may do so in different ways.
– If we are interested in every phonetic detail, we
would indicate effects like aspiration in English,
even if it is not distinctive
– If we are interested more in the phonological
inventory, we would omit the aspiration, as it is not
distinctive
• For our purposes we will be concentrating
mostly on the latter type
• When we focus on phonology, an abstract
representation, we use slashes, e.g. /p/
Phonemes and Allophones, cont.
•
•
So, to continue with our example, the phoneme /p/
appears in each of the following words:
pit
spit
Remember that we are interested in generalizations
about sound structure. In particular, the rule for
aspiration in English is like this:
1. English voiceless stops are
a. Aspirated if word initial, or syllable-initial
preceding a stressed vowel:
Compare récord vs. recórd
b. Otherwise unaspirated.
Phonemes and their distributions
• Above we saw some simple minimal pairs of words
that illustrate how we determine what the phonemes
of a language are
• Other cases of distinctive features lead to some
interesting observations
• Consider the nasals:
– rum
run
rung
• These phonemes can all appear at the end of the
word; but, [ng], unlike the other two, has the property
that it never occurs word-initially in English
– map
nap
*ngap
• Although it occurs only at the end of the word, it’s still
a phoneme, as seen in run vs rung, or sin vs. sing,
etc.
Applying some thinking
• One way of seeing whether or not we are dealing
with two different phonemes or two allophones of the
same phoneme involves what is called
complementary distribution.
• We have already seen some things about distribution
before
– For example, /ng/ does not occur in word-internal position
• Think now about our minimal pairs like pill and bill. In
these words, the p and b sounds occur in the same
distributional position (word-initially)
• Another way of putting this is that the p sound and
the b sound have a shared distribution; that is, they
are not in complementary distribution, where one is
found where the other is not
Distribution…
• Consider /f/ and /v/ in this light. In Modern English it
is easy to find minimal pairs:
– fat vs. vat
– safer vs. saver
• I.e., these sounds are not in complementary
distribution. They are two phonemes.
• In Old English, though, this was not the case:
–
–
–
–
–
–
hlaford [v] ‘lord’
æfter [f] ‘after’
heofon [v] ‘heaven’
fisc [f] ‘fish’
ofer [v] ‘over’
healf [f] ‘half’
Cross-Linguistic Differences
• Some sound differences are systematic in a lanuage,
but are not phonemic. In another language, though,
that sound difference might be phonemic….
• Everyone has encountered a language that contains
a speech sound that is not in their native language
• As a general point, languages differ greatly both in
terms of how many phonemes they have and in
terms of which phonemes they have
– Number of phonemes:
• Many: Some Khoisan languages, around 140
phonemes
• Few: E.g. Hawaiian, 13 phonemes
Other languages
• Like it says above, languages have different numbers of
phonemes
• In some cases, a contrast that is not phonemic in one language
is phonemic in another
• E.g. Hindi has contrastive voiced/voiceless like English, but
aspiration is also contrastive:
bal ‘hair’
pal ‘take care of’
phal ‘knife blade’
dal ‘lentil’
tal ‘beat’
thal ‘plate’
gal ‘cheek’
kal ‘era’
khal ‘skin’
Listen to these (and more…) at:
http://www.phonetics.ucla.edu/vowels/chapter12/hindi.html