Kevin McMullin and Gunnar Ólafur Hansson. Poster presented at LabPhon 14. July 25-27, 2014 in Tokyo, Japan.

1. Induc<ve
learning
of
long-­‐distance
dissimila<on
as
a
problem
for
phonology
1.
Background
Kevin
McMullin
and
Gunnar
Ólafur
Hansson
University
of
Bri-sh
Columbia
Consonant
harmony
Ar-ficial
language
learning
(harmony)
• Two consonants must agree for some feature value
• Two attested variants of locality (Rose & Walker 2004, Hansson 2010)
1. Unbounded harmony holds at any distance within the relevant domain
2. Transvocalic harmony applies across at most one vowel
Illustration of the typological split in two Omotic languages
Unbounded sibilant harmony in Aari (Hayward 1990)
a. /baʔ-s-e/ baʔse ‘he brought’
b. /tʃʼa̤ːq-s-it/ tʃʼa̤ːqʃit ‘I swore’
c. /ʃed-er-s-it/ ʃederʃit ‘I was seen’
Transvocalic sibilant harmony in Koyra (Koorete; Hayward 1982)
a. /tim-d-osːo/ tindosːo ‘he got wet’
b. /patʃ-d-osːo/ patʃːoʃːo ‘it became less’
c. /ʃod-d-osːo/ ʃodːosːo ‘he uprooted’
• The attested split is mirrored in the results of adult phonotactic learning for
sibilants (Finley 2011, 2012) and liquids (McMullin & Hansson in press)
…Cv-Cv …Cvcv-Cv Cvcvcv-Cv
Unbounded + + +
Transvocalic + – –
unattested – + –
unattested – + +
unattested + + –
Ques-ons
• Do humans learn and generalize long-distance consonant dissimilation in the
same way as harmony?
• How do these biases relate to learnability and formal complexity?
4.
Discussion
(Dis)Agreement
by
(Non)Correspondence
Formal-­‐computa-onal
perspec-ve
• CORR constraints induce a surface correspondence relation (C↔C) on co-occurring
segments that are sufficiently similar
• “CC-Limiter” constraints impose conditions on corresponding segments
(e.g. agreement in some additional [F], structural relations)
CORR-[Rhotic] (Bennett 2013)
If two co-occurring consonants are both [Rhotic], they must stand
in C↔C correspondence (indicated by subscript indices).
CC-EDGE(morpheme) (Bennett 2013)
Segments in C↔C correspondence must be tautomorphemic.
CC-SYLLADJ (Bennett 2013; cf. PROXIMITY in Rose & Walker 2004)
Segments in C↔C correspondence must be in the same or adjacent
syllables (slightly simplified definition).
• Inability to enforce CC-Limiter demands may trigger dissimilation as a
repair (avoiding the need for C↔C correspondence)
• Languages can be considered stringsets whose phonotactics can be modeled
with a formal grammar that identifies (un)grammatical strings (words)
• Complexity of a phonotactic pattern can be assessed based on its membership
in certain well-defined classes of formal languages (e.g. subregular languages)
Strictly Local languages (SL)
• Not computationally complex, defined in terms of k-factors (n-grams)
• Learnable in the limit from positive data for any fixed k (Heinz 2010)
• Bounded co-occurrence restrictions are Strictly Local
e.g. Transvocalic liquid dissimilation is SL3: *rVr, but rV…Vr is permitted
• Unbounded co-occurrence restrictions are not SLk (they hold at length k+1)
Tier-based Strictly Local languages (TSL; Heinz et al. 2011)
• Properly include the SL languages
• Defined in terms of k-factors amongst a subset of the inventory (tiers)
• Tiers can be defined in terms of features, natural classes, or arbitrarily
Examples of tier-based substrings for a word pilemoru
Future
studies
• How do learners deal with overt evidence of an unattested locality type (e.g.
beyond-transvocalic-only dissimilation/harmony)?
• Can learners discover (or infer) phonotactic patterns of dissimilation/harmony
with blocking by intervening segments of certain kinds?
• What is the appropriate characterization of the “transvocalic” relation?
Syllable-adjacency? Consonant-tier adjacency? Onset-tier adjacency?
• Are there restrictions on the set of possible tiers, or on the relationship between
a tier T and the set of targeted 2-factors (bigrams) on that tier?
Possible
theory-­‐internal
solu-ons
• Add special versions of CORR constraints that are limited to a CVC
window (Hansson 2010, Bennett 2013) – resolves ranking paradox for
transvocalic-only dissimilation
• Abandon CC-SYLLADJ from CC-Limiter constraint class – removes
beyond-transvocalic-only dissimilation from the factorial typology
2.
Methodology
Experimental
design:
Three
phases
Example
s-muli
1. Practice: Initial exposure to six CVCV-LV stem-suffix pairs in two tenses
2. Training:192 triplets with suffix-triggered liquid dissimilation
• Each of three groups differed only in the stems encountered in training
Control: No liquids – intended to reveal any underlying biases
Nontransvocalic: 96 CVCVCV stems, 96 CVLVCV
Transvocalic: 96 CVCVCV stems, 96 CVCVLV
3. Testing: Subjects heard a stem followed by two options with the same suffix
• Choice between liquid harmony vs. disharmony (2AFC task)
• 32 trials for stems at each of three trigger-target distances (96 total trials)
• Short- (CVCVLV), Medium- (CVLVCV), and Long-range (LVCVCV)
➤
➤
➤
➤
➤
“Past tense” – toke…toke-li; “Future tense” – mebi…mebi-ru
Stimuli were presented over a set of headphones and repeated aloud
tikemu…tikemu-li…tikemu-ru; bipobe…bipobe-ru…bipobe-li
giluko…giruko-li…giluko-ru; norego…nolego-ru…norego-li
pokuri…pokuri-li…pokuli-ru; depile…depile-ru…depire-li
dotile…dotile-li or dotire-li; tukiri…tukiri-ru or tukili-ru (Short-range)
teriti…teliti-ru or teriti-ru; bilegi…bilegi-ru or biregi-ru (Medium-range)
linode…linode-li or rinode-li; renitu…lenitu-li or renitu-li (Long-range)
3.
Results
and
analysis
Mixed-­‐effects
logis-c
regression
• Dependent variable: Was disharmony chosen on a particular trial?
• Random by-subject intercepts and slopes for disharmony second/faithful
References Acknowledgements
Bennett, William. 2013. Dissimilation, consonant harmony, and surface correspondence. Doctoral
dissertation, Rutgers University.
Finley, Sara. 2011. The privileged status of locality in consonant harmony. Journal of Memory and
Language 65:74–83.
Finley, Sara. 2012. Testing the limits of long-distance learning: learning beyond a three- segment
window. Cognitive Science 36:740–756.
Hansson, Gunnar Ólafur. 2010. Consonant harmony: long-distance interaction in phonology.
Berkeley: University of California Press.
Hayward, Richard J. 1982. Notes on the Koyra language. Afrika und Übersee 65:211–268.
Hayward, Richard J. 1990. Notes on the Aari language. In Omotic language studies, ed. R. J.
Hayward, 425–493. London: School of Oriental and African Studies.
Heinz, Jeffrey. 2010. Learning long-distance phonotactics. Linguistic Inquiry 41(4): 623–661.
Heinz, Jeffrey, Chetan Rawal and Herbert G. Tanner. 2011. Tier-based strictly local constraints for
phonology. Proceedings of the 49th Annual Meeting of the Association for Computational
Linguistics, pp. 58–64. Association for Computational Linguistics.
McMullin, Kevin and Gunnar Ólafur Hansson. In press. Locality in long-distance phonotactics:
evidence for modular learning. To appear in Proceedings of NELS 44, ed. Jyoti Iyer and Leland
Kusmer. GLSA Publications, University of Massachusetts.
McNaughton, Robert, and Seymour Papert. 1971. Counter-free automata. Cambridge, MA: MIT
Press.
Rose, Sharon, and Rachel Walker. 2004. A typology of consonant agreement as correspondence.
Language 80:475–531.
This research was supported by SSHRC Insight Grant 435–2013–0455 to Gunnar Ólafur
Hansson and a UBC Faculty of Arts Graduate Research Award to Kevin McMullin. Special
thanks to Carla Hudson Kam and the UBC Language and Learning Lab, as well as to Jeff
Heinz, Alexis Black, James Crippen, Ella Fund-Reznicek and Michael McAuliffe
LabPhon
14,
NINJAL,
Tokyo,
Japan,
July
25-­‐27,
2014
Unbounded (attested)
/CVrV-rV/ CC-SYLLADJ CC-EDGE CORR-[Rhotic] IDENT[lat]-IO
! a. CV.lxV-ryV *
b. CV.rxV-rxV * W L
c. CV.rxV-ryV * W L
/rVCV-rV/ CC-SYLLADJ CC-EDGE CORR-[Rhotic] IDENT[lat]-IO
! a. lxV.CV-ryV *
b. rxV.CV-rxV * W * W L
c. rxV.CV-ryV * W L
Transvocalic (attested): RANKING PARADOX
/CVrV-rV/ CORR-[Rhotic] CC-EDGE IDENT[lat]-IO CC-SYLLADJ
! a. CV.lxV-ryV *
b. CV.rxV-rxV * W L
c. CV.rxV-ryV *! W L
/rVCV-rV/ CORR-[Rhotic] CC-EDGE IDENT[lat]-IO CC-SYLLADJ
a. lxV.CV-ryV L * W L
" b. rxV.CV-rxV *! *
c. rxV.CV-ryV *! W L L
Beyond-transvocalic-only (unattested?)
/CVrV-rV/ CC-SYLLADJ CORR-[Rhotic] IDENT[lat]-IO CC-EDGE
a. CV.lxV-ryV *! W L
! b. CV.rxV-rxV *
c. CV.rxV-ryV *! W L
/rVCV-rV/ CC-SYLLADJ CORR-[Rhotic] IDENT[lat]-IO CC-EDGE
! a. lxV.CV-ryV *
b. rxV.CV-rxV *! W L * W
c. rxV.CV-ryV *! W L
Type of test item (trigger-target distance)
Short-range Medium-range Long-range
Nontransvocalic
vs. Control
4.11
p < 0.001
3.19
p < 0.001
1.49
p ≈ 0.236
Transvocalic
vs. Control
8.75
p < 0.001
1.39
p ≈ 0.292
0.83
p ≈ 0.539
Table of Odds Ratios comparing disharmony choices between experimental and
control groups after releveling the mixed logit model at each testing distance.
Coefficient Estimate SE Pr(>|z|)
Intercept –0.7090 0.2704 0.009
Disharmony second –0.6089 0.1205 <0.001
Disharmony faithful 2.2224 0.3318 <0.001
Medium-range –0.0459 0.1837 0.803
Long-range 0.1887 0.1827 0.302
Nontransvocalic 1.4132 0.3414 <0.001
Nontransvocalic × Medium-range –0.2508 0.2656 0.345
Nontransvocalic × Long-range –1.0195 0.2631 <0.001
Transvocalic 2.1695 0.3309 <0.001
Transvocalic × Medium-range –1.8385 0.2742 <0.001
Transvocalic × Long-range –2.3643 0.2753 <0.001
Summary of the fixed effects portion of the logit mixed model (N = 3404;
log-likelihood = –1666.9; baseline level of unfaithful disharmony being
chosen by the Control group in the first item of a Short-range trial)
Regular
languages
Locally
Testable
Tier-­‐based
Strictly
Local
Strictly
Piecewise
Star-­‐Free
Locally
Threshold
Testable
Strictly
Local
Piecewise
Testable
Figure illustrating the subregular hierarchy (McNaughton & Papert 1971,
Heinz et al. 2011; see also Heinz 2010, Rogers & Pullum 2011).
vowels T = {i, e,o,u} pilemoru
consonants T = {p, l,m, r} pilemoru
liquids T = {l, r} pilemoru
arbitrary T = {o, l,m, p} pilemoru
Short-range
(cvcvLv-Lv)
Medium-range
(cvLvcv-Lv)
Long-range
(Lvcvcv-Lv)
Locality levels (test-item types)
Proportion disharmony responses ([r…l] or [l…r])
0.00 0.25 0.50 0.75 1.00
Nontransvocalic group Control group Transvocalic group Locality ABC? TSL2? Formal properties
Unbounded ✔ ✔
TSL2 for T = {l, r} (all liquids)
Bigram restrictions: {*ll,*rr}
Transvocalic ✗ ✔
TSL2 for T = {C, l, r} (all consonants)
Bigram restrictions: {*ll,*rr}
Beyond-transvocalic-only
✔ ✗
Not TSLk for any value of T or k
If T = {C, l, r} then for any banned k-factor r Cn r (with
k = n+2), the longer r Cn+1 r must also be banned.
If T = {l, r}, then k relates to the number of liquids in
the word, not their distance from each other.