The%20Role%20of%20Features%20in%20Phonological%20Inventories

1
The Role of Features in Phonological Inventories

• Feature geometries  from phonology to syntax /
  Les géométries de traits  de la phonologie à la
  syntaxe
• Paris, le samedi 3 décembre 2005

• Nick Clements
• clements_at_ext.jussieu.fr
• Laboratoire de Phonétique et Phonologie (UMR
  7018)
• CNRS / Paris Universitas

2
A word of thanks to those who have made this
conference possible ...

• For making this day possible
• the UMR 7023 (Université de Paris 8)
• the Fédération Typologie et Universaux
  Linguistiques (TUL), CNRS FR 2559

For making the topic possible
Euclid of Alexandria (325 BC-265 BC), the most
prominent mathematician of Antiquity. His
treatise on geometry, the Elements, the only
textbook of Antiquity still in use today, has
influenced all branches of science.
3
"There is no royal road to geometry"
4
Organization of this talk

• Part 1. Two geometries of feature organisation
• Part 2. (Some) principles of inventory
  structure
• Part 3. Case study the feature nasal

5
A feature geometry tree
Source Avery and Rice (1989)
Root
Properties 1. Each node lies on a
separate autosegmental tier (example)
2. Constituents correspond to sets of features
that function as a unit in phonological rules of
spreading, deletion, etc. (example) 3. The
constituent structure is proposed as universal,
not subject to parametric variation 4. Constituent
s usually correspond to independent articulators
or regions of the vocal tract
Laryngeal
continuant
voice
Supralaryngeal
Sonorant
nasal
lateral
Place
Labial
Coronal
Dorsal
round
distributed
6
A feature geometry tree
Source Avery and Rice (1989)
Root
A node is justified if and only if a rule of some
language targets it. Examples
Laryngeal
continuant
voice
Supralaryngeal
Sonorant
- in Berber, all Root features of stops are
geminated in the imperfect - in Korean, all
Laryngeal features are deleted in the syllable
coda - in Spanish, nasals assimilate to a
following consonant in all Place features - in
Basque roots, sibilants agree in all Coronal
features
nasal
lateral
Place
Labial
Coronal
Dorsal
round
distributed
7
A feature geometry tree
Source Avery and Rice (1989)
Root
Constraint on rules Any rule may operate on
one and only one node in the tree. All
subordinate nodes, but no superordinate nodes are
affected. For example, a rule
may target the Place node, deleting it. All
dependent features delete with it.
Laryngeal
continuant
voice
Supralaryngeal
Sonorant
nasal
lateral
Place
Labial
Coronal
Dorsal
round
distributed
8
A feature geometry tree
Source Avery and Rice (1989)
Root

• 2 major predictions
• 1. Only sets of features forming
  constituents are directly affected by
  phonological rules.
• These potential sets are the same from
  language to language.

Laryngeal
continuant
voice
Supralaryngeal
Sonorant
nasal
lateral
Place
Labial
Coronal
Dorsal
round
distributed
9
A second type of feature tree
10
A feature hierarchy
(adapted from Clements 2001)
This tree displays the 14 commonest
consonantal sounds in the UPSID
database (Maddieson Precoda 1989) Upper-case
letters represent types of sounds as
characterized by the features that dominate them,
e.g. P any voiceless labial obstruent
sonorant
_ _ _ _ _ _
posterior
_ _ _ _ _ _
_ _ _ _ _ _
-
_ _ _ _ _ _
continuant
_ _ _ _ _ _
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A feature hierarchy tree
consonantal
Properties 1. Features are ranked
in a hierarchy of preference, from
top to bottom 2. Feature ranking is based on
the crosslinguistic frequency of
contrasts 3. Ranking is partial six
tentative ranks are shown above (separated
by dashed lines) 4. Ranking is universal
(strongest version) or
probabilistic (weaker version) 5.
Rooted feature paths define natural
classes of sounds
-

sonorant
-
-


labial
-
dorsal

_ _ _ _ _ _
posterior
-
-


_ _ _ _ _ _
strident
-

_ _ _ _ _ _
voiced
-
-
-



_ _ _ _ _ _
-
-
continuant


_ _ _ _ _ _
-
lateral

P B K G T D S TS N L R J

M W
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A feature hierarchy tree
consonantal
Constraints on tree construction 1. The
subset of features chosen by any given
language must conform to the ranking 2.
All nonterminal nodes must branch (thus
there are no redundant feature
specifications)
-

sonorant
-
-


labial
-
dorsal

_ _ _ _ _ _
posterior
-
-


_ _ _ _ _ _
strident
-

_ _ _ _ _ _
voiced
-
-
-



_ _ _ _ _ _
-
-
continuant


_ _ _ _ _ _
-
lateral

P B K G T D S TS M W N L R J
13
A feature hierarchy tree
consonantal
? An ill-formed subtree non-terminal
nodes fail to branch. Such a tree would specify
the redundant feature voice for sonorants.
-

sonorant
-
-


labial
-
dorsal

_ _ _ _ _ _
posterior
-
-


_ _ _ _ _ _
strident
-

_ _ _ _ _ _
voiced
-
-
-








_ _ _ _ _ _
-
-
continuant


_ _ _ _ _ _
-
lateral

P B K G T D S TS M W N L R J
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A feature hierarchy tree
consonantal
Predictions 1. Inventories tend to
employ higher-ranked features before employing
lower-ranked features 2. Inventories tend to
expand from top down (historical change,
acquisition, etc.) 3. Inventories tend to
contract from bottom up (historical change,
aphasia, etc.)
-

sonorant
-
-


labial
-
dorsal

_ _ _ _ _ _
posterior
-
-


_ _ _ _ _ _
strident
-

_ _ _ _ _ _
voiced
-
-
-



_ _ _ _ _ _
-
-
continuant


_ _ _ _ _ _
-
lateral

P B K G T D S TS M W N L R J
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A feature hierarchy tree
consonantal
Predictions (cont.) 4. If a given
contrast appears within a marked category (), it
also appears in the corresponding unmarked
category (-) 5. For any constituent, the least
marked sound of the unmarked branch is more
frequent than the least marked sound of the
marked branch
-

sonorant
-
-


labial
-
dorsal

_ _ _ _ _ _
posterior
-
-


_ _ _ _ _ _
strident
-

_ _ _ _ _ _
voiced
-
-
-



_ _ _ _ _ _
-
-
continuant


_ _ _ _ _ _
-
lateral

P B K G T D S TS M W N L R J
3 10 2 14 1 12 7 11 5 8 4 9 13
6 ? UPSID frequency rank
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The two models compared
feature geometry tree feature hierarchy tree
what does it model? segments segment inventories
universal structure? yes yes
phonetic motivation? mostly articulatory mostly auditory
predicts rule types? yes no
predicts inventory structure? no yes
represents segmental markedness? yes (see below) yes (see below)
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Segmental markedness can be directly represented
in both theories

• Feature Geometry tree only marked features are
  present (in some versions)
• -- as a result, markedness is directly reflected
  in the number of nodes.
• Example the representation of t vs. m
  (following Avery and Rice 1989).

Root t
Root m
Laryngeal
Laryngeal
Supralaryngeal
Supralaryngeal
Sonorant
Place
Place
nasal
Labial
t 3 nodes
m 6 nodes
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Segmental markedness can be directly represented
in both theories

• In the Feature Hierarchy tree, marked features
  are plus-specified (Clements 2001)
• As a result, markedness is directly reflected in
  the number of plus-specifications.
• Example the representation of t vs. m.

consonantal
sonorant
-

labial
-
-


dorsal
-

-
-
posterior


strident
-

-
-
-
voiced



-
-
continuant


-
lateral

P B K G T D S TS M
W N L R J
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Summary

• In phonology,
• -- Feature geometry represents natural classes
  of features (those that function together as a
  unit), while the feature hierarchy represents a
  hierarchy of natural classes of sounds (sounds
  that function together as a unit)
• -- Rules are better expressed by the feature
  geometry, but Inventory structure is better
  represented by the feature heirarchy, as it is
  specifically designed for this purpose
• -- Markedness relations can be directly
  represented in both models

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Part 2. (Some) principles of inventory structure
21
Observation not just any set of consonants and
vowels can make up a sound system

• -- a central finding of the earliest work in
  phonology was that sound systems are structured
  in terms of regular correlations defined in terms
  of features (see e.g. Trubetzkoy 1969/1939,
  Hockett 1955)
• -- the current project is to search for the
  principles that define inventory structure

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The theory of inventories presented here is based
on the following main components

• -- The Feature Hierarchy
• -- Feature Economy
• -- Markedness Avoidance
• -- Enhancement Theory

We now go on to consider the latter three, and
their interactions.
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Feature Economy "maximize feature combinations"

• Languages tend to maximize the combinatory
  possibilities of features within their
  inventories of speech sounds in other words,
  features present in one segment tend to be used
  to define others.
• The feature economy of any given system can be
  quantified in terms of a measure called its
  economy index. Given a system with S speech
  sounds and in which F features are required to
  characterize them, its economy index E can be
  given (to a first approximation) by the
  expression
• E S/F
• The higher the value of E, the greater the
  economy.
• Feature economy can be defined as the tendency to
  maximize E.

Martinet 1955 Clements 2003a, 2003b
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Markedness Avoidance "avoid marked feature
values"

• Feature economy is counteracted by the tendency
  to avoid marked feature values
• Examples of widely avoided segment types
• -- laryngealized vowels
• -- nasalized fricatives
• -- voiceless nasals
• Markedness Avoidance Within any class of sounds
  in which a given feature F is potentially
  distinctive, sounds bearing the marked value of F
  lt ("are less frequent than") sounds bearing the
  unmarked or null value of F.
• -- In other words, languages tend to avoid marked
  feature values, regardless of the class of sounds
  they occur in.

Jakobson 1941, Greenberg 1966, Calabrese 1994,
Clements 2005
25
A standard variety of English 24 consonants

• ph th tSh kh
• b d dZ g
• f T s S
• v D z Z
• m n N
• w l r y h

• voiced and continuant are used with
  near-maximal efficiency
• nasal creates nasal stops at three of the four
  available places of articulation
• but there are a number of significant gaps,
  corresponding to marked feature combinations

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Phonological enhancement "enhance weak auditory
contrasts"

• Enhancement can be achieved by introducing
  redundant features.
• Marked feature values are favored for this
  purpose when they serve an enhancing function.
• Example rounded (a marked feature value)
  frequently enhances the contrast between front
  and back high and mid vowels
• for instance, / i u / offers a better
  auditory contrast than / i ö /
• --- As a result, if a language has just two high
  vowels, it is most likely to have / i / and
  / u /.

(Stevens Keyser 1989, 2001, etc.)
27
Phonological enhancement "enhance weak auditory
contrasts"

• However, such cases counteract Markedness
  Avoidance
• In most contexts, the marked value rounded is
  less frequent than its absence, as we expect (for
  example, rounded consonants are less frequent
  than plain consonants)
• It is just in the class of high and mid vowels
  that the expected trend is reversed the marked
  value rounded is more frequent than its
  unmarked counterpart -rounded (or Ørounded)
• Even in such cases of "frequency reversal", the
  value rounded remains marked by most other
  criteria (e.g. spreading of marked values,
  neutralization to the unmarked value)

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Summary what the model predicts

• 1. For a marked feature value M and its
  unmarked counterpart value U, in any class of
  sounds,
• Economy M U
• "the number of segments bearing the marked value
  M is equal to the number of segments bearing
  the unmarked value U"
• example voiced fricatives (a marked category)
  should be as numerous as voiceless fricatives
  (their unmarked counterparts)
• ... recall English

29
A standard variety of English 24 consonants

• ph th tSh kh
• b d dZ g
• f T s S
• v D z Z
• m n N
• w l r y h

• voiced fricatives are just as numerous as
  voiceless fricatives (a Feature Economy effect)

30
Summary what the model predicts

• 2. Markedness Avoidance
• M lt U
• "the number of segments bearing the marked value
  M is less than the number of segments bearing the
  unmarked value U"
• example voiced fricatives (a marked category)
  should be less numerous than voiceless
  fricatives (their unmarked counterparts)
  this is true in German, for example
• This prediction contradicts the previous one.
  Both cannot be right in one and the same
  comparison. The expectation is that one will win
  out in some cases, and the other in others.

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Summary what the model predicts

• 3. Enhancement
• Menh gt U (Menh a marked enhancing feature
  value)
• "the number of segments bearing a marked
  enhancing value Menh is greater than the number
  of segments bearing the unmarked value U"
• Again, this prediction contradicts the previous
  one. However, they are in complementary
  distribution Enhancement applies to a special
  subset of cases in which Markedness Avoidance
  applies (those in which the marked feature value
  plays an enhancing role).

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Summary what the model predicts

• The interaction of these principles thus predicts
  the following
• In any class of sounds and for any feature F, if
  M is an enhancing feature Menh, then M gt U
  otherwise, M ? U.
• _________________________
• Note It is assumed here that Enhancement always
  takes precedence over Feature Economy. This is
  true of all cases reported in Clements (2005).

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Part 3. Case study the feature nasal
34
nasal is marked
nasal is marked with respect to -nasal by
nearly all criteria, for example

• all languages have oral sounds, but some lack
  nasal sounds
• oral sounds are more frequent than nasal sounds
• nasal frequently spreads, while -nasal
  rarely if ever does

Some phonologists, following the original
intuition of Trubetzkoy (1939), regard nasal as
a (marked) privative feature.
35
Predictions

• 1) M ? U
• 2) Menh gt U

because either nasal -nasal (by Feature
Economy) or nasal lt -nasal (by Markedness
Avoidance), because nasal gt -nasal in
enhancing contexts
36
Data base

• Evidence is drawn from the expanded UPSID data
  base (Maddieson Precoda 1989)
• contains 451 phoneme inventories (representing
  6-7 of the world's languages)
• geographically and genetically balanced
• electronic database, facilitating rapid searches
• results can be independently verified by others
• Results are statistically evaluated for
  significance of trends

Maddieson 1991, Clements 2003
37
Case 1 Nasality in obstruents

• nasal is absent in obstruents, or rare (12.6
  of the sample languages) if we analyze
  prenasalized sounds such as NT or NZ as nasalized
  obstruents.
• This result is as expected (M lt U).

38
Case 2 Nasality in vowels

• 100 of the sample languages have oral vowels,
  but only 22.6 have nasal vowels.
• This result is again as expected (M lt U).
• But nasal vowels are rather well represented in
  the world's languages. Are there some languages
  in which nasal vowels outnumber oral vowels
  (contrary to the predictions)?

39
Nasal vowel systems (diphthongs excluded)

• type A M lt U type B M U type C M gt U
• (nasal vowels lt oral vowels) (nasal vowels
  oral vowels) (nasal vowels gt oral vowels)
• i "â u u) i "â u u) i "â u
  u)
• e o e e) o o) e) o)
• a a) a a) a a)

next commonest 46
unattested 0
commonest 56
40
Distribution of nasal vowel systems
Group Group total Type A Type B Total AB
South American 66 11 25 36
Niger-Congo 55 19 7 26
North American 65 14 5 19
Indo-European 23 4 4 8
Papuan 39 1 3 4
Sino-Tibetan 21 2 1 3
Khoisan 4 2 0 2
Austro-Tai 14 1 0 1
Caucasian 7 0 1 1
Dravidian 6 1 0 1
Nilo-Saharan 23 1 0 1
Totals 56 46 102
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This result is as expected

• Type A systems (M lt U) respect Markedness
  Avoidance, but violate Feature Economy
• Type B systems (M U) respect Feature Economy,
  but violate Markedness Avoidance
• Type C systems (M gt U) violate both Feature
  Economy and Markedness Avoidance
• N.b. The absence of languages having only nasal
  vowels is just the limit case of Type C.

42
Case 3 Nasality in sonorant consonants

• In the class of sonorant consonants overall,
  nasal sounds are disfavored, but only by a
  small margin as shown below (the larger of the
  two figures is bolded)
• oral sonorants 447 languages (unmarked)
• nasal sonorants 435 languages (marked)

43
Case 3 Nasality in sonorant consonants

• However, if we carry out separate comparisons on
  continuants (rhotics, glides, other nonlateral
  approximants) and noncontinuants (nasal stops and
  laterals), a striking dissymmetry emerges

-nasal nasal
A. sonorant continuants 433 w j R 5 w) jâ Râ
B. sonorant noncontinuants 368 l 435 m n ø
...
44
Case 3 Nasality in sonorant consonants

• In class A, the unmarked -nasal value is
  overwhelmingly favored, as expected. -- But in
  class B we find a "frequency reversal" in which
  segments bearing marked nasal are the more
  frequent

-nasal nasal
A. sonorant continuants 433 w j R 5 w) jâ Râ
B. sonorant noncontinuants 368 l 435 m n ø
Why should this be so?
45
nasal enhances -continuant in the class of
sonorant sounds

• The release of a nasal consonant "results in a
  significantly greater increase in the spectrum
  amplitude over a wide frequency range than does
  the release of a lateral consonant" (Stevens
  Keyser 1989 92)

That is, the acoustic mark of the feature
-continuant an abrupt increase in amplitude
at the consonant-vowel boundary is more abrupt
at the release of nasal stops than at the release
of oral stops. The claim is that nasals offer a
better contrast than laterals to sonorant,
continuant sounds that is, the class of
rhotics, glides, etc. In this view, for example,
for any vowel V,
/ nV / vs. / rV / makes a better contrast than
/ lV / vs. / rV /
46
Testing the claim
If this explanation is correct, systems
contrasting / nV / vs. / rV / should outnumber
those contrasting / lV / vs. / rV /. This
prediction can be tested.

• Let us consider the distribution of nasals and
  laterals in "R-systems" systems containing at
  least one an R-sound (such as / R/ or / r/ ) and
  just one noncontinuant sonorant series, either
  nasal or lateral, at the anterior coronal place
  of articulation (where all widely occur). Such
  systems fall into one of two types
• type A R N
• type B R L
• The expectation is that type A systems should be
  more numerous

47
Testing the claim

• The prediction is correct
• Type A (R N) 54
• Type B (R L ) 2
• That is, in "R-systems", the noncontinuant series
  is almost invariably nasal rather than lateral
  (c2 20.446, plt.0001)
• The two-term Type A system /N R/ is
  overwhelmingly preferred to the two-term Type B
  system /L R/, as is predicted by Enhancement
  Theory.
• _______________________________
• In systems lacking R-sounds, N is also commoner
  than L, but by a smaller and statistically
  non-significant margin (Clements 2005).

48
Summary

• We find, then, that the model correctly predicts
  the distribution of nasal and -nasal sounds
  across phoneme inventories.
• M ? U either nasal -nasal (by Feature
  Economy) or nasal lt -nasal (by Markedness
  Avoidance), but
• Menh gt U nasal gt -nasal in enhancing
  contexts.
• The marked value nasal is less frequent than
  -nasal in most sound classes, as predicted by
  Marked Feature Avoidance, but it is more frequent
  than -nasal in systems in which continuant and
  noncontinuant sonorants contrast, as predicted by
  Phonological Enhancement.

49
Our current project

• ... is to continue exploring the factors that
  condition sound inventories. Components of this
  research include studies of

• inventory structure across the world's languages
  and within particular areas (Africa)
• phonetic bases of distinctive features within the
  context of quantal/enhancement theory (Stevens
  Keyser)
• phonological acquisition, both normal and deviant
  (Portuguese, French, ...)
• the internal structure of particular languages
  (Ikwere project, with S. Osu)

50
Some References

• Avery, Peter Keren Rice. 1989. "Segment
  structure and coronal underspecification,"
  Phonology 1989, 179-200.
• Clements, G.N. 2001. "Representational Economy
  in Constraint-based Phonology." In T. Alan Hall
  (ed.), Distinctive Feature Theory, 71-146.
  Berlin Mouton de Gruyter.
• Clements, G.N. 2003. "Feature Economy in Sound
  Systems", Phonology 20.3, 287-333
• Clements, G.N. 2005. "The Role of Features in
  Speech Sound Inventories." To appear in Eric
  Raimy Charles Cairns, eds., Contemporary Views
  on Architecture and Representations in
  Phonological Theory. Cambridge, MA MIT Press.
• Halle, Morris. 1959. The Sound Pattern of
  Russian a Linguistic and Acoustical
  Investigation. The Hague Mouton. Reprinted
  1971.
• Hockett, C.F. 1955. A Manual of Phonology.
  (Memoire 11 of IJAL 21.4, Part 1.) Baltimore
  Waverley Press. Reprinted by the University of
  Chicago Press, 1974
• Maddieson, Ian Karen Precoda. 1989.
  "Updating UPSID," UCLA Working Papers in
  Phonetics 74. 104-111.
• Martinet, André. 1955. Economie des changements
  phonétiques Traité de phonologie diachronique.
  Berne Francke. Second revised edition
  Maisonneuve Larose, Paris, 2005.
• Stevens, Kenneth N. Samuel Jay Keyser. 1989.
  "Primary features and their enhancement in
  consonants," Language 65.1, 81-106.
• Trubetzkoy, N.S. 1939. Grundzüge der Phonologie,
  Göttingen Vandenhoeck Ruprecht. English
  edition Principles of Phonology, tr. C.A.M.
  Baltaxe. Berkeley and Los Angeles University of
  California, 1969.

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• Vive Euclide!

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