Conditions%20for%20Divergence%20and%20Convergence%20in%20the%20Micro-Evolution%20of%20Language

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Conditions for Divergence and Convergence in the
Micro-Evolution of Language
William Labov, University of Pennsylvania
Penn Linguistics Colloquium March 27, 2009
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No scientific theory is worth anything unless it
enables us to predict something which is actually
going on
. J.B.S. Haldane, cited by P. R. Grant
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1. When two groups are separated so that
   communication between them is reduced, then
   divergence is expected, and any degree of
   convergence requires an explanation.
2. When two groups are in continuous communication,
   linguistic convergence is expected and any degree
   of divergence requires an explanation.

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Growing divergence in North American English
Recent studies of linguistic change in progress
in North American English show increasing
diversity on a regional scale, along with some
degree of local convergence.
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The dialects of North American English
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Divergence in North American Dialects
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The Northern Cities Shift from the Project on
Cross-Dialectal Comprehension Gating Experiment 2
Word Phrase
Sentence 1. _________ ________________
___________________________ 2. _________
________________ ___________________________ 3.
_________ ________________ ____________________
_______ 4. _________ ________________
___________________________ 5. _________
________________ ___________________________ 6.
_________ ________________ ____________________
_______
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Percent correct in Gating Experiment for Chicago
busses with the antennas on top
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Age distribution of F2 of /?/ in the North
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Age distribution of F2 of /?/ in the Midland
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Age distribution of F2 of /?/ in the North and
the Midland
North
Midland
age coefficient - 2.05
p .026
age coefficient 1.39
p .033
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Divergence in North American Dialects
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Relationships among Americas Most Populous
Metropolitan Areas
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Three suggested parallels of linguistic and
biological evolution

• Probability matching (Gallistel 1990)
• ? the mechanism of chain shifting
• Microevolution (P. R. Grant 1993)
• ? the mechanism of divergence
• Animal communication systems (Cheyney Seyfarth
  200
• ? the social motivation of linguistic change

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The Canadian Shift
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Probability matching
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Mean number of out of 33 ducks in front of
experimenter 1 as a function of time and rate of
throwing food (Gallistel 1990)
Experimenter 1 every 5 seconds every 10
seconds Experimenter 2 every 5 seconds every
5 seconds
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Martinet on maximal dispersion
Phonemes co-existing in a language tend
naturally to optimize the possibilities that are
available from the speech organs they tend to be
as distant from their neighbors as possible while
remaining easy to articulate and easy to
perceive. . . Martinet 195562 (tr. WL),
attributed to de Groot TCLP 1931121
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A stable distribution of English low vowels an
outlier not recognized as a member of the /o/
distribution.
/o/
/æh/
/oh/
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An unstable distribution of English low vowels
/æh/ shifted up and front so that the /o/
outlier affects the central tendency of /o/
/æh/
/o/
/oh/
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Opposing chain shifts in North America
Northern Cities Shift
Southern Shift
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Model of divergence
The divergence of neighboring dialects
requires alternating states of bidirectional
changes followed by unidirectional changes in the
form of mergers or chain shifts
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A model of requirements for divergence
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Micro-evolution
The fluctuations of bidirectional changes
resemble the micro-evolution of finch beaks in
the Grants' study of the Galapagos, although no
correlate of fitness or natural selection has yet
been identified for the linguistic changes
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Bidirectional micro-evolution
The population of medium ground finches, Geospiza
fortis, experienced size-selective mortality
during a drought in 1976-77 large birds with
deep beaks survived better than small birds.
During another drought, 1984-1986, the population
experienced selection in the opposite direction
on beak traits. Changes in food supply were the
apparent causes of selection on beak traits in
both episodes. --Grant, Peter R. and B. Rosemary
Grant 1994. Predicting microevolutionary
responses to directional selection on heritable
variation. Evolution 49241-251.
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The initiation of divergence
a1, a2
Equally likely resolution of an unstable
linguistic situation
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The initiation of divergence
Nasal system tense all /æ/ before nasals
General tensing and raising of all /æ/-gt /æh/
Reversible
a1, a2
Inconsistent mixture of short-a tensing patterns
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The initiation of divergence
Northern Cities Shift blocked
Northern Cities Shift
Nasal system tense all /æ/ before nasals
General tensing and raising of all /æ/-gt /æh/
a1, a2
Inconsistent mixture of short-a tensing patterns
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The development of divergence
Northern Cities Shift
Canadian Shift
Irreversible
Inland North front /o/
Back vowel shift
Irreversible
) ) )
Low back merger
Increase phonetic distance
Eastern seaboard raise /oh/
Pittsburgh chain shift
South add upglide
Back upglide chain shift
Reversible
Irreversible
/o/ /oh/
Skewed opposition depending on length
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Natural selection ( ? )
To summarize, the co-existence of finch species
is facilitated by divergence in beak morphology
and song. Beaks diverge under natural selection,
but why songs diverge is less clear. Cultural
drift, a process of random change in culturally
transmitted (learned) traits, is probably
involved, and sexual selection may be learned as
well.
What Darwin's Finches Can Teach Us about the
Evolutionary Origin and Regulation of
Biodiversity B. Rosemary Grant and Peter R.
Grant, Bioscience, Vol. 53, No. 10 (Oct., 2003),
pp. 965-975
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Beak evolution
Evolution of beak depth of Geospiza fortis for
survivors of 1976 drought, for 1976 offspring and
1978 offspring. --B. P. Grant 2003.
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Cheney and Seyfarth on the role of social
intelligence
Baboons adaptive specialization is their social
intelligence their technological skills are
underwhelming. . .Although innovation, tool use,
and technological invention may have played a
crucial role in the evolution of ape and human
brains, these skills were probably built upon
mental computations that had their origins and
foundations in social interactions. --Cheney and
Seyfarth 2007283.
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Social factors as adaptive forces in linguistic
behavior. . .
Biological terminology Sociolinguistic
terminology
Territoriality Local identity Dominance and
submission Style shifting and accommodation
Sexual selection The social construction of
gender
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Gender and social category determination of five
elements of the Northern City Shift in a Detroit
suburban high school
?
æ
Source Eckert 2000
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Acts of identity
The individual creates his systems of verbal
behavior so as to resemble those common to the
group or groups with which he wishes from time to
time to be identified, to the extent that (a)
he is able to identify those groups (b) his
motives are sufficiently clear-cut and powerful
(c) his opportunities for learning are adequate
(d) his ability to learn -- that is, to changes
his habits where necessary -- is unimpaired.
--R. Le Page A. Tabouret-Keller, Acts of
Identity (1985)
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Social correlates of four measures of the
Northern Cities Shift N71
Age Female Years of 25
yrs Gender Education AE1 34
8.6 EAEQ 34 26 EOD 112 H.S.
-68 UOD 37 -16
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A consideration on large-scale social factors
African-Americans in Memphis appear to be moving
toward forms which symbolize involvement in the
Southern community and its associated heritage. .
. While social unity was a part of the
communities of practice explored by Eckert, I
would expand her framework to suggest that these
shared practices do not necessarily require
individuals social cohesion but merely require
shared historical experience and a strongly
circumscribing environment that places speakers
in a similar social position relative to the
external social world. ----Fridland 2000
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A large scale phenomenon
The Northern Cities Shift is found throughout the
Inland North, an area of 88,000 square miles. A
population of over 34,000,000 speakers of
American English are participating in this shift.
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The U.S. at night
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U.S. at Night
The Inland North
Grand Rapids
Milwaukee
Syracuse
Rochester
Chicago
Flint
Buffalo
Detroit
Cleveland
Kenoshat
Joliet
Toledo
Omaha
Columbus
St. Louis
CIncinnati
Indianapolis
Kansas City
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Red States and Blue States in U.S. 2004
Presidential election
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The Northern dialect region mapped on to Red
States and Blue States in U.S. 2004 Presidential
election
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Presidential elections in which the Northern
States NY, MI, WI, IA, MN have been opposed to
the Southern States TX, AK, LA, MI, AL, GA, FL,
SC, NC, KY,TN, VA
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Democratic vs. Republican vote for counties
surveyed by dialect in presidential election of
2004.
Inland North Midland
New North England Kerry majority 20
15 8 12 Bush majority 6
7 13 2
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County vote for Kerry 2004 by county vote and
dialect
Kerry
Bush
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Regression analyses of county percent vote for
Kerry in 2004 by dialect groups with and without
total votes as independent variable. Residual
group Midland
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County vote for Obama 2008 by county vote and
dialect
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Regression analysis of 2008 Obama vote by county
Variable Coefficient prob
Constant 57.25 0.0001
Inland North 3.21 0.056
Mid-Atlantic 7.75 0.021
New England 4.44 0.071

r2 .065
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Passage 1 in Experiment 1 (from Sabrina K., 37,
Detroit MI, TS 176)

• short o fronting
• short a raising
• oh lowering

The--the way I got hired for this one job was
really weird, cause I went in for a . . .
secretarial position is what I went in for, and
they had hired. . .ah-- somebody else that didnt
know anything, but it was a buyers daughter, so
then she got the job. And uh--they called me
because I had done shipping and receiving as far
as--the paper work, and they had asked me if Id
help out cause their--shipper had just had a
heart attack and she wasn comin back for a
while.
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The Northern Cities Shift of Sabrina K., 37
1994, Detroit MI, TS 176
Short-i
Short-u
Short-a
Short-e
Long open o
Short-o
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Passage 2 in Experiment 1 (from Mimi P., 45
2000, Indianapolis IN, TS 775)

• short o back of center
• tense a before nasals lax a, e in that
• aw fronting
• fronting

I read, a-n-nd like most women, I like to go
shopping and play card games with family and
friends and that kind of thing, nothing really
exciting. We used to go camping quite a bit on
the weekends, but our lives have shifted enough
that we dont do that much right now, but uh
thats what we do.
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Dialect areas in which U. of Indiana subjects
were raised 4-13 yrs of age
Dialect area of listeners N
Inland North 9
Chicago 9
North (outside of IN) 1
Transitional (Ft. Wayne) 3
Midland 58
Indianapolis 4
Indiana 50
Other Midland 4
Mid-Atlantic 6
Canada 1
South 4
West 6
Mixed 2
90
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Cities assigned to Detroit and Indianapolis
speakers by student listeners at Indiana
University N90
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Political opinions ascribed to an Inland North
(Detroit) and Midland (Indianapolis) speaker by
students at U. of Indiana, Bloomington N90
No significant difference in judgments of
intelligence, trustworthiness, education Midland
speaker judged more friendly (p lt .00001)
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Ideological, political and linguistic
developments, 1817-2008
Party of racial equality
Yankee ideology
Yankee settlement
Non Cities Shift
Expansion in western NY
1825-50 Raising of short-a
1817-1825
Evangelical movement
Westward expansion
Perfectionism
1830-1860
Opposition to racial inequality
1856 Republican
1860-1956
1967 Fronting of /o/ first reported
1960-1995
1960 Democratic
Switch of political allegiance
1986 Backing of /?/ first reported
2000-2008
Blue States /Red States redefined
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Means of 14 vowels in peripheral/nonperipheral
phonological space. IN Inland North
IN /æ/
IN /?/
IN /e/
IN /o/