Gestural overlap and self-organizing phonological contrasts

Contrast in Phonology, University of TorontoMay 3-5, 2002

Alexei KochetovHaskins Laboratories/Yale University

Thanks to

• The Project on Contrast in Phonology– SSHRC grants (410-99-1309 and 410-96-0842)

to Elan Dresher and Keren Rice, University of Toronto

– http://www.chass.utoronto.ca/~contrast

Introduction

• Restrictions on phonological contrasts– Backness and rounding in high vowels– Secondary articulations in consonants

• Account: – These markedness effects emerge from low-

level speaker-listener/learner interactions – The crucial role of production and perception of

contrasts

Phonological contrasts

• Focus:– Contrasts in high vowels

• Front/back, rounded/unrounded

• Inventories /i y u/, /i y u/, or /i u/

– Contrasts in consonant secondary articulations• Palatalized vs. non-palatalized: /C C(/w)/

• Labialized vs. non-labialized: /Cw C(w/)/

• Velarized vs. non-velarized: /C C()/

Observations

• UPSID Database (Maddieson & Precoda 1990) – 451 languages

Observations

• Languages with multiple vowel contrasts avoid distinctions in secondary consonant articulations– e.g. /y/ but */Cj/ (C = plosive; 2 exceptions)

Observations

• Languages with distinctive secondary articulation contrasts tend to avoid multiple vowel contrasts, particularly distinctions in rounding/backness– e.g. /Cw/ but */y/ (C = plosive; 1 exception)

Observations

• Inventories of languages of Northern and Eastern Europe – 37 languages (Celtic, Germanic, Baltic, Uralic

and Turkic)

Observations

KarelianFaroese

IcelandicNenets

Saami

Mordva

Chuvash

Mari

Tatar

Bashkir

Question

• Why are these contrasts incompatible?

?

Explanation

• Approach 1– These markedness effects are pre-specified in

Universal Grammar• Harmonic rankings of constraints (Optimality

Theory; Prince & Smolensky 1993)

• Phonological representations

• Approach 2– These markedness effects arise due to lower-

level factors -- limitations on production and perception

– Work in phonology and phonetics: • Browman & Goldstein 1986, 2002; Ohala 1981;

Hume & Johnson 2001, Pierrehumbert, Beckman, & Ladd 2001, among others

• Cf. Jackendoff 2002 on markedness in general

Explanation

Explanation

• Approach 2– These markedness effects arise due to lower-

level factors -- limitations on production and perception

– Work in phonology and phonetics: • Browman & Goldstein 1986, 2002; Ohala 1981;

Hume & Johnson 2001, Pierrehumbert, Beckman, & Ladd 2001, among others

• Cf. Jackendoff 2002 on markedness in general

Explanation

• Approach 2– Self-organization, or spontaneous emergence of

order (see e.g., Kauffman 1995)

• dynamic systems

• AI and ALife (see e.g., Pfeifer & Scheier 2001)

Self-organization

From www. swarm.org

Simple local interaction Spontaneous emergence of order

Self-organization and phonology

Phonological structure

Speaker-listener interactions

Self-organization and phonology

• Markedness effects• Unmarked:

– stable with respect to production and/or perception, and/or higher-level processing

– An equilibrium position

• Marked: – unstable with respect to production, and/or perception,

and and/or higher-level processing

– A non-equilibrium position

Simulation

• Speaker-listener/learner interactions

• Autonomous agents – Cf. Browman & Goldstein 1999, de Boer 2000,

Lieberman 2000, Harrison, Dras & Kapicioglu 2002

A hypothetical language

• Language X

• Inventory: – {i y u} – {C C C C}

• Lexicon: – C1VC2 words, where C1= C2

– 16 items

Language X

#

C CiC CyC C C CuC 4

C C iC C yC C C C uC 4

C CiC CyC C C CuC 4

C C iC C yC C C C uC 4

# 4 4 4 4

Lexical items

Speaker-listener interactions

Agent A Agent B

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

* From www.zabaware.com

*

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Speaker-listener interactions

Signal Production Perception

Lexicon and

Grammar

Lexicon and

Grammar

Signal Perception Production

Agent A Agent B

Production

• Articulatory synthesizer (Maeda 1989, Vallée1994)

• Articulatory gestures (targets)

• Vectors of numbers between 0 and 1– Backness [0 . . . 1]– Height [0 . . . 1]– Rounding [0 . . . 1]

Production

• Rounding [1]

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

Production

• Rounding [0.75]

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

Production

• Rounding [0.5]

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

Production

• Rounding [0.25]

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

Production

• Rounding [0]

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

Production

• Vowels

• Backness Height Rounding

• i = [ 0 1 0 ]

Production

• Vowels

• Backness Height Rounding

• y = [ 0 1 1 ]

Production

• Consonants (secondary articulation)

• Backness Height Rounding

• C = [ 0 1 0 ]

Production

• Consonants (secondary articulation)

• Backness Height Rounding

• C = [ 0 1 1 ]

Production

• Words– Matrices of numbers between 0 and 1

e.g., CuC C u C0 1 0

1 1 1

0 1 0

Production

• Words: sequences of gestures overlapping in time

C V C

Production: Gestural overlap

• Gestures have conflicting targets

• Physical limits on how well targets can be attained

• An “undershoot” of at least one of the gestures (Lindblom 1963)

• Stiffness (GEST, Computational gestural model; Browman & Goldstein 1990)

Production: Gestural overlap

• Stiffness, kC = 1, kV = 1;

• No reduction; physically impossible

C V C

Production: Gestural overlap

• Stiffness, kC = 1, kV = 0.75

• Vowel gesture is reduced

C V C

Production: Gestural overlap

• Evidence: – In languages with secondary articulation

vowels are strongly affected by the secondary articulation quality of neighboring consonants

– Russian (Bolla 1981, Kochetov 2001)– Irish (Ó Dochartaigh 1992 ) – Marshallese (Choi 1992)

Production: Gestural overlap

• Stiffness, kC = 0.75, kV = 1• Consonant gestures (secondary articulation) are

reduced

C V C

Production: Gestural overlap

• Evidence: – In languages with multiple backness and

rounding contrasts consonants are often allophonically palatalized and velarized/labialized

– Turkic languages (Comrie 1981)

Simulation

• Item: CuC • Case 1: Vowel gesture is

reduced– kC = 1, kV = 0.5

• Case 2: Consonant gestures are reduced– kC = 0.5, kV = 1

Case 1

• kC = 1, kV = .5

• Input: CuC• Output: CC or CyC

Case 2

• kC = 0.5, kV = 1

• Input: CuC• Output: CuC or CuC

Case 1: Lexicon and grammar

Agent A

#

C CiC CyC C C CuC 4

C C iC C yC C C C uC 4

C CiC CyC C C CuC 4

C C iC C yC C C C uC 4

# 4 4 4 4

Case 1: Lexicon and grammar

Agent B

#

C 4

C 4

C 4

C 4

# 4 4 4 4

Case 1: Lexicon and grammar

Agent B

#

C CiC CyC C C *CuC 3

C C iC C yC C C *C uC 3

C *CiC CyC C C CuC 3

C *C iC C yC C C C uC 3

# 2 4 4 2

Case 1: Lexicon and grammar

Agent B

#

C CiC *CyC C C *CuC 2

C *C iC C yC C C *C uC 2

C *CiC CyC C C *CuC 2

C *C iC C yC *C C C uC 2

# 1 3 3 1

Case 1: Lexicon and grammar

• Default grammar 1: – limited vowel contrasts (front vs. back)– multiple consonant contrasts in secondary

articulation (restricted in distribution)

Case 2: Lexicon and grammar

Agent A

#

C CiC CyC C C CuC 4

C C iC C yC C C C uC 4

C CiC CyC C C CuC 4

C C iC C yC C C C uC 4

# 4 4 4 4

Case 1: Lexicon and grammar

Agent B

#

C 4

C 4

C 4

C 4

# 4 4 4 4

Case 2: Lexicon and grammar

Agent B

#

C CiC CyC *C C *CuC 2

C C iC C yC C C C uC 4

C CiC CyC C C CuC 4

C *C iC *C yC C C C uC 2

# 3 3 3 3

Case 2: Lexicon and grammar

Agent B

#

C CiC *CyC *C C *CuC 1

C *C iC C yC C C C uC 3

C CiC CyC C C *CuC 3

C *C iC *C yC *C C C uC 1

# 2 2 2 2

Lexicon and grammar

• Default grammar 2: – multiple vowel contrasts (restricted in

distribution)– limited consonant contrasts in secondary

articulation (front vs. back)– consonants realizations are often close to

neutral (non-palatalized, non-labialized, etc.)

Lexicon and grammar

• Grammar 0: unstable

• Grammar 1: more stable

• Grammar 2: more stable

Lexicon and grammar

• Default grammar 3: – limited vowel contrasts– limited consonant contrasts in secondary

articulation

Conclusion

• The incompatibility of vowel and secondary articulation contrasts emerges through speaker-listener/learner interactions – Unstable (marked) Stable (unmarked)

• No reference to pre-specified “knowledge” of markedness

Limitations

• The simulation does not explain certain segmental markedness effects – e.g. /y/ is more marked than /i/– // is more marked than /u/

• Markedness is a by-product of multiple factors

Further directions

• Implementation: additional factors– Other sequences, primary place of articulation

– More realistic production and perception

– More complex generalizations across the Lexicon and Grammar

– Higher-level processing: morphological structure and alternations

– Multiple agents: speakers/listeners

• Other phonological contrasts

Further directions

• Towards a better understanding of the phonological Grammar and markedness

END