In contrast to assimilation, dissimilation, metathesis, and
haplology tend to occur more sporadically, i.e., to affect
individual words. Dissimilation involves a change in one of two
'same' sounds that are adjacent or almost adjacent in a particular word
such that they are no longer the same. Thus the first "l" in English colonel is changed to an "r", and the word is pronounced
like "kernel". Metathesis involves the change in order of two
adjacent sounds. Crystal cites Modern English third from
OE thrid, and Modern English bird is
a parallel example. But Modern English bright underwent
the opposite change, its ancestor being beorht, and not
all "vowel + r" words changed the relative order of these segments as
happened with bird and third. Already
by the time of Old English, there were two forms of the word for "ask":
ascian and acsian. We don't know which
form was metathesized from the other, but we do know that ascian
won out in the standard language. Haplology is similar to dissimilation,
because it involves getting rid of similar neighboring sounds, but this
time, one sound is simply dropped out rather than being changed to a different
sound. An example is the pronunciation of Modern English probably as prob'ly.
Linguistics 001     Lecture 22    Language
Change

## Types of Language Change

Language is always changing. We've seen that language changes across
space and across social group. Language also varies across time.

Generation by generation, pronunciations evolve, new words are borrowed
or invented, the meaning of old words drifts, and morphology develops
or decays. The rate of change varies, but whether the changes are faster
or slower, they build up until the "mother tongue" becomes arbitrarily
distant and different. After a thousand years, the original and new languages
will not be mutually intelligible. After ten thousand years, the relationship
will be essentially indistinguishable from chance relationships between
historically unrelated languages.

In isolated subpopulations speaking the same language, most changes will
not be shared. As a result, such subgroups will drift apart linguistically,
and eventually will not be able to understand one another.

In the modern world, language change is often socially problematic. Long
before divergent dialects lose mutual intelligibility completely, they
begin to show difficulties and inefficiencies in communication, especially
under noisy or stressful conditions. Also, as people observe language
change, they usually react negatively, feeling that the language has "gone
down hill". You never seem to hear older people commenting that the language
of their children or grandchildren's generation has improved compared
to the language of their own youth.

Here is a puzzle: language change is functionally disadvantageous, in
that it hinders communication, and it is also negatively evaluated by
socially dominant groups. Nevertheless is is a universal fact of human
history.

## How and why does language change?

There are many different routes to language change. Changes can take
originate in language learning, or through language contact,
social differentiation, and natural processes in usage.

Language learning: Language is transformed as it is transmitted
from one generation to the next. Each individual must re-create a grammar
and lexicon based on input received from parents, older siblings and other
members of the speech community. The experience of each individual is
different, and the process of linguistic replication is imperfect, so
that the result is variable across individuals. However, a bias in the
learning process -- for instance, towards regularization -- will cause
systematic drift, generation by generation. In addition, random differences
may spread and become 'fixed', especially in small populations.

Language contact: Migration, conquest and trade bring speakers
of one language into contact with speakers of another language. Some individuals
will become fully bilingual as children, while others learn a second language
more or less well as adults. In such contact situations, languages often
borrow words, sounds, constructions and so on.

Social differentiation. Social groups adopt distinctive norms
of dress, adornment, gesture and so forth; language is part of the package.
Linguistic distinctiveness can be achieved through vocabulary (slang or
jargon), pronunciation (usually via exaggeration of some variants already
available in the environment), morphological processes, syntactic constructions,
and so on.

Natural processes in usage. Rapid or casual speech naturally produces
processes such as assimilation, dissimilation, syncope
and apocope. Through repetition, particular cases may become conventionalized,
and therefore produced even in slower or more careful speech. Word meaning
change in a similar way, through conventionalization of processes like
metaphor and metonymy.

Some linguists distinguish between internal and external
sources of language change, with "internal" sources of change
being those that occur within a single languistic community, and contact
phenomena being the main examples of an external source of change.

## The analogy with evolution via natural selection

Darwin himself, in developing the concept of evolution of species via
natural selection, made an analogy to the evolution of languages. For
the analogy to hold, we need a pool of individuals with variable traits,
a process of replication creating new individuals whose traits depend
on those of their "parents", and a set of environmental processes
that result in differential success in replication for different traits.

We can cast each of the just-listed types of language change in such
a framework. For example, in child language acquisition, different grammatical
or different lexical patterns may be more or less easily learnable, resulting
in better replication for grammatical or lexical variants that are "fitter"
in this sense.

There are some key differences between grammars/lexicons and genotypes.
For one thing, linguistic traits can be acquired throughout one's life
from many different sources, although intitial acquisition and (to a lesser
extent) adolescence seem to be crucial stages. Acquired (linguistic) traits
can also be passed on to others. One consequence is that linguistic history
need not have the form of a tree, with languages splitting but
never rejoining, whereas genetic evolution is largely constrained to have
a tree-like form (despite the possibility of transfer of genetic material
across species boundaries by viral infection and so on). However, as a
practical matter, the assumption that linguistic history is a sort of
tree structure has been found to be a good working approximation.

In particular, the basic sound structure and morphology of languages
usually seems to "descend" via a tree-structured graph of inheritance,
with regular, lawful relationships between the patterns of "parent"
and "child" languages.

## Types of Change

### Sound change

All aspects of language change, and a great deal is know about general
mechanisms and historical details of changes at all levels of linguistic
analysis. However, a special and conspicuous success has been achieved
in modeling changes in phonological systems, traditionally called sound
change. In the cases where we have access to several historical stages
-- for instance, the development of the modern Romance Languages from
Latin -- these sound changes are remarkably regular. Techniques developed
in such cases permit us to reconstruct the sound system -- and some of
the vocabulary -- of unattested parent languages from information about
daughter languages.

In some cases, an old sound becomes a new sound across the board. Such
a change occurred in Hawai'ian, in that all the " t" sounds in an
older form of the language became " k"s: at the time Europeans encountered
Hawai'ian, there were no " t"s in it at all, though the closely
related languages Tahitian, Samoan, Tongan and Maori all have " t"s.

Another unconditioned sound change that occurred between Middle
and Early Modern English (around Shakespeare's time) is known as the Great
Vowel Shift. At that time, there was a length distinction in the English
vowels, and the Great Vowel Shift altered the position of all the
long vowels, in a giant rotation.

The nucleus of the two high vowels (front "long i" /i:/, and the back
"long u" /u:/) started to drop, and the high position was retained only
in the offglide. Eventually, the original /i:/ became /ai/ - so a "long
i" vowel in Modern English is now pronounced /ai/ as in a word like 'bite':
/bait/. Similarly, the "long u" found its nucleus dropping all the way
to /au/: the earlier 'house' /hu:s/ became /haus/. All the other long
vowels rotated, the mid vowels /e:/ and /o:/ rising to fill the spots
vacated by the former /i:/ and /u:/ respectively, and so on. That is why
the modern pronouns 'he' and 'she' are written with /e/ (reflecting the
old pronunciation) but pronounced as /i/. In the following chart, the
words are located where their vowel used to be pronounced
-- where they are pronounced today is indicated by the arrows.



In other cases, a sound change may be "conditioned" so as to
apply in certain kinds of environments and not in others. For example,
it's very common for tongue-tip ("coronal") consonants to become
palatal when they are followed by high front vowels. The residue of this
process can be seen in English pairs like divide/division, fuse/fusion,
submit/submission, oppress/oppression.

#### Processes of sound change.

Another dimension along which we can look at sound change is by classifying
changes according to the particular process involved.

Assimilation, or the influence of one sound on an adjacent sound,
is perhaps the most pervasive process. Assimilation processes changed
Latin /k/ when followed by /i/ or /y/, first to /ky/, then to "ch", then
to /s/, so that Latin faciat /fakiat/ 'would make' became
fasse /fas/ in Modern French (the subjunctive of the
verb faire'to make').Palatalization is a kind of assimilation.

In contrast to assimilation, dissimilation, metathesis, and
haplology tend to occur more sporadically, i.e., to affect
individual words. Dissimilation involves a change in one of two
'same' sounds that are adjacent or almost adjacent in a particular word
such that they are no longer the same. Thus the first "l" in English colonel is changed to an "r", and the word is pronounced
like "kernel". Metathesis involves the change in order of two
adjacent sounds. Crystal cites Modern English third from
OE thrid, and Modern English bird is
a parallel example. But Modern English bright underwent
the opposite change, its ancestor being beorht, and not
all "vowel + r" words changed the relative order of these segments as
happened with bird and third. Already
by the time of Old English, there were two forms of the word for "ask":
ascian and acsian. We don't know which
form was metathesized from the other, but we do know that ascian
won out in the standard language. Haplology is similar to dissimilation,
because it involves getting rid of similar neighboring sounds, but this
time, one sound is simply dropped out rather than being changed to a different
sound. An example is the pronunciation of Modern English probably as prob'ly.

Other sound change processes are merger, split, loss, syncope, apocope,
prothesis, and epenthesis. Merger and split can be
seen as the mirror image of each other. A merger that is currently
expanding over much of the United States is the merger between "short
o" and "long open o". The following table contains examples
of words that you probably pronounce differently if you are from the Philadelphia
- New York - New England area, or if you are from the South. If you are
from Canada, the American Midwest, or from California, you probably find
that the vowels in these pairs sound the same, rather than different.
If this is the case, you have a merger here.

Short "o"****Long "Open o"****cot

hot

hock

stock****caught

haughty

hawk

stalk

Splits are rarer than mergers, and usually arise when a formerly
conditioned alternation loses the environment that provided the original
conditioning, and the previously conditioned alternation becomes two independent
sounds that contrast with each other. This is basically what happened
when /f/ and /v/ split in English ( /v/ having previously
been an alternate of /f/ when /f/ occurred in an intervocalic
position).

Loss involves the loss of a sound from a language, as when
Hawai'ian lost the /t/ in favor of /k/ (see below).

Syncope and apocope are the loss of medial and final
sounds respectively. Middle English 'tame' in the past tense was /temede/. It lost both its medial and final vowels to become Modern English
/teymd/. These are usually conditioned changes that
do not involve loss of the same sound elsewhere.

Prothesis and epenthesis are the introduction of additional
sounds, initially and medially respectively. The addition of the /e/
that made Latin words like scola 'school' into Portuguese escola is the only example of prothesis in foure historical linguistics
textbooks I consulted. As for epenthesis, an example other than the one
Crystal cites was the /d/ inserted into ME thunrian to give
us the Modern English thunder.

### How do we know how languages are related?

Linguists rely on systematic sound changes to establish the relationships
between languages. The basic idea is that when a change occurs within
a speech community, it gets diffused across the entire community of speakers
of the language. If, however, the communities have split and are no longer
in contact, a change that happens in one community does not get
diffused to the other community. Thus a change that happened between early
and late Latin would show up in all the 'daughter' languages of Latin, but
once the late Latin speakers of the Iberian peninsula were no longer in
regular contact with other late Latin speakers, a change that happened there
would not spread to the other communities. Languages that share innovations
are considered to have shared a common history apart from other languages,
and are put on the same branch of the language family tree.

Words in two or more daughter languages that derive from the same word
in the ancestral language are known as cognates. Sound changes
work to change the actual phonetic form of the word in the different languages,
but we can still recognize them as originating from a common source because
of the regularities within each language. For example, a change happened
in Italian such that in initial consonant clusters, the l that
originally followed p and f changed to i. Thus
Italian words like fiore 'flower'; fiume 'river'; pioggia 'rain'; and piuma 'feather' are cognates with the French
fleur; fleuve; pluie; and plume, respectively, and with
Spanish flora, fluvial (adj. 'riverine'); lluvia (by a
later change); and pluma respectively.

In the Romance languages below, the word for 'mother' is a cognate in
all the six contemporary languages considered, however the word for 'father'
is a cognate only in four of the five: in Rumanian, the original word
inherited from Latin pater has been replaced by a completely
different word, tata.

Spanish and Italian are the only two that retain a phonological reflex
of the original Latin medial consonant t, (in both languages,
it has been voiced to d, probably a change that occurred in the
common ancestor to all the dialects and languages of the Iberian peninsula.
All the other Romance languages have dropped it. The original r
has also suffered different fates: however, within each language, the
same thing happened in both words. Where we find r deleted in
final position in the word for 'mother', we also find it deleted in the
same position in the word for 'father'.

English Gloss

_French**Italian**Spanish**Portuguese**Rumanian__Catalan_mother mer madre madre mae mama marefatherperpadre padre pae tata pare

The same principles are applied in languages that do not have a written
history. Several cognate sets in five languages of the Polynesian family
are listed in the next table.

English

Gloss

_Tongan**Maori**Samoan**Tahitian**Hawai'ian_1. bird manu manu manu manu manu2. fishikaika i?a i?a i?a3. to eatkaikai?ai?ai?ai4. forbidden tapu tapu tapu tapu kapu5. eye mata mata mata mata maka6. bloodtoto toto toto toto koko

We see that no changes happened in the nasal consonants, nor in the
vowels, but we can observe in lines 2 and 3 that wherever Tongan and Maori
have /k/, Samoan, Tahitian and Hawai'ian appear to have /?/
(glottal stop). Apparently there has been an unconditioned change from
/k/ to /?/ in the Eastern branch, or a change from /k/ to /k/ in the Western branch of this family. We choose
the first as more likely, partly because /t/ is a more common phoneme
in the world's languages, partly because backing of consonants is more
common than fronting, and partly because of what we know about the culture
history: Polynesia was peopled from west to east, and if the change had
occurred in the Western branch, that would have been at a time when all
five languages were still one speech community. Next, we see in lines
4 - 6 that there is a systematic correspondence between /t/ in
the first four languages and /k/ in the easternmost, Hawai'ian.
This looks like another systematic, unconditioned sound change, this time
in only one language. (We can see from this example that when English
borrowed the Polynesian word for "forbidden", we borrowed it from one
of the languages west of Hawaii -- we say "taboo", not "kaboo").
This is what a family tree of the five Polynesian languages would look
like, based on the small data set above (the picture is somewhat more
complex when we look at other cognate sets -- Maori in particular is probably
not correctly placed in this diagram, which has been designed as an illustration
of the method):



## Historical Reconstruction vs. Lexicostatistics

In the examples just discussed, the central enterprise has been to establish
a systematic pattern of change, most often sound change: every
original Malayo-polynesian /t/ becomes /k/ in Hawaiian, and we can cite
many correspondences of cognate pairs to prove it. This level of
understanding is useful for several reasons.

First, a systematic pattern of phonological correspondence across many
words is unlikely to have arisen by chance, whereas completely unrelated
languages often develop surprising similarities in particular words, entirely
by chance.

Second, given systematic patterns of this type, we can start to apply
the comparative method to reconstruct the parent language. This
in turn allows us to examine relationships among reconstructed languages
at a greater time depth, even if the process of change entirely obscures
the relationships among the vocabulary items in the child languages.

However, establishing patterns of this type is difficult. It requires
a large vocabulary in all the languages being compared, in order to find
enough cognates; and it also requires a deep knowledge of the grammar
of each of the languages, in order to see cognate relationships that might
be obscured by morphology and contextual phonological change -- and not
to be fooled into seeing false cognates where morphology or phonology
have created chance similarities.

Another approach, pioneered by the American Structuralist linguist Morris
Swadesh, is called lexicostatistics. For a set of languages
of interest, we get a small vocabulary list of common, basic words (typically
100-200 items). For each pair of languages, we determine the percentage
of words on this list that appear to be cognate. Determination of cognation
is dependent on the subjective judgment of the linguist, and we expect
some errors, especially if the scholar does not know the languages very
well, but we hope that the error rate will be small enough not to affect
the results.

We can then arrange these cognate percentages in a table, from which
we draw some conclusions about the degree of relationship among the languages
involved.

Here is a recent example, drawn from Central   
Yambasa Survey Report, by Boone et al., discussing languages of the
Centre Province of Cameroon:

Gunu [two lists]  82  Elip  85  90  Mmala [two lists]  78  90  89  Yangben[two lists]  77  81  81  88  Baca [two lists]  66  72  72  77  78  Mbule [two lists]  58  63  64  66  70  69  Bati  42  41  42  42  42  46  45  Hijuk [two lists]  39  38  41  38  37  40  41  88  Basaa

Table 5 New lexical similarity percentages for
Central Yambasa

and selected neighbouring tongues

From this table, we can conclude that Elip, Mmala and Yangben are "closely
related speech varieties"; that they are somewhat more distant from
Gunu, Baca and Mbule; that they are even more distant from Bati; and that
they are further yet from Hijuk and Basaa. Based on this sort of consideration,
we can construct a sort of family tree, just as we might based on patterns
of sound change.

There has been a great deal of controversy about whether family trees
based on lexicostatistics are reliable. Those who doubt it point to the
possibility that cognate percentages might be strongly affected by vocabulary
borrowing, either in a negative or positive direction. For instance, Japanese
borrowed many words from Chinese without becoming a Sino-Tibetan language;
it has recently borrowed many words from English without becoming an Indo-European
language. Those who favor lexicostatistics argue that this sort of borrowing
is less common in the basic-vocabulary wordlists that they use.

There are two distinct controversies about the use of lexicostatistical
methods. One issue is whether the family trees produced for languages
with fairly high cognate percentages (say 60% and higher) are a reliable
indication of the detailed structure of "genetic" relationships
among languages. Everyone accepts that two languages with 85% cognates
are certainly related; the only question is whether they are (necessarily)
"more closely related" in a historical sense than either is
to a language whose cognate percentages with both are (say) 80%.

For example, we might have a situation in which proto-language A splits
into B and C. C in turn splits into D and E. E then undergoes a period
of close contact with a completely unrelated language, Z, as a result
of of which it borrows a lot of new vocabulary. Now E has a lower cognate
percentage with D than D has with B; but the historical fact is that E
is more closely related to D than D is to B.

The second controversy is what to make of relationships involving very
low cognate percentages, say below 10%. Depending on the nature of the
languages and the methods used to determine cognation, these percentages
are getting into the range that could (it is argued) arise by chance,
or by superficial or indirect recent contact.

### Glottochronology

Swadesh and others took this type of analysis further, based on the idea
that the average rate of loss of cognates could be regarded as constant
over historical time, just like the rate of radioactive decay. Swadesh
looked at some languages where historical stages are well documented,
and concluded that basic vocabulary decays by 14 percent every millenium.
According to the entry on Swadesh in the Encyclopedia of Linguistics:

Everyone recognizes that linguistic decay is not completely uniform.
Some people still believe that it is sometimes uniform enough for glottochronological
methods to be a useful approximate guide to linguistic (and thus ethnic)
history.

## What are the results of language change?

When accompanied by splits of populations, language change results first
in dialect divergence (the kinds of differences we see between British and
American English; between the French of France and of Quebec; between New
World and Old World Spanish and Portuguese). Over longer time periods, we
see the emergence of separate languages as in the contemporary Romance languages,
separated by about 2000 years, and the Germanic languages, whose divergence
began perhaps 500 years earlier. Both of these families are part of Indo-European, for which the Ethnologue web page lists 425 languages! Though political
considerations often intervene in whether a particular speech variety is
considered to be a language or a dialect, the basic idea behind linguistic
classifications is that dialects are mutually intelligible, whereas languages
are not.

Of course, the question of intelligibility is always relative. The following
phrases taken from the spontaneous speech of Chicagoans recorded in the
early 1990s were difficult for many non-Chicagoans to understand correctly.
In "gating" experiments designed to test cross-dialectal comprehension
in American English, subjects first heard a word, then a slightly longer
segment, then a whole phrase or sentence that may have disambiguated the
original mishearing. These experiments were part of the research project
on Cross-Dialectal Comprehension done at the Linguistics Lab here at Penn
(for more information on the Northern Cities Shift, see "The Organization
of Dialect Diversity" on the home page of the Phonological   
Atlas of North America.)

_Original segment**Many people misheard as**First expansion__Second expansion_drop  ??? (nonsense word containing vowel in "that") massive drop

the plane was steady for a while and then it took a massive drop

sockssacks y'hadda wear socks y'hadda wear socks, no sandalsblockblackone block old senior citizens living on one blockmetmutt they met  my parents went to Cuba and that's where they metsteadystudysteady for a while the plane was steady for a while and then it took a massive dropheadhadshook 'er head this woman in while, who just smiled at her and shook 'er head

These misunderstandings are based on the fact that the Chicago speakers
(along with 40 - 50 million other people in the "Inland North" dialect
including Rochester, Buffalo, Detroit, Syracuse, and other cities of that
region) have a rotation of their short vowels such that the low unrounded
vowel of the "short o" words like drop, socks, block,
and hot is being fronted to the position where other
American dialects have words like that, hat, black, rap,
and sacks, , and where "short e" words like met,
steady and head can sound like mutt,
study and thud or mat, static
and had.

The Ethnologue data base
includes more than 6700 languages spoken in 228 countries. They state
that their "criterion for listing speech varieties separately is low intelligibility,
as far as that can be ascertained."

### How far back can we go?

Most linguists agree that our methods for reconstruction will take as only
as far back as about 5000 - 7000 years; after that, the number of cognate
sets available for reconstruction becomes just too low to give results that
can be reliably distinguished from chance relationships. Although it would
be very satisfying to be able to link up some of the existing families at
a higher level, the evidence seems too weak to allow us to do so. A minority
of scholars, however, argue that this is possible, and one particularly
well-known group of such scholars goes by the name of Nostraticists, derived
from their views that there exists a super-family of language they have
called the "Nostratic". A New York Times article from 1995 presents a well-balanced
view of the Nostraticist position. Dr. Donald Ringe of the Penn Linguistics Department, himself an expert
on the ancient Indo-European language Tocharian, is one of the chief critics
of the Nostraticist position.