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- This talk is about combinatoriality
in the evolution of human language.
The big problem in talking about
and researching the evolution
of human language is finding relevant evidence.
One thing we know for sure,
we can't go back and reconstruct
some original language of all humanity
by tracing back today's languages,
so we have to look for other sources of evidence.
Today, I'm gonna focus on languages
that have originated much more recently,
the sign languages that are used
in communities of deaf people
and communities of deaf and hearing people.
First, the idea of combinatoriality.
What's the difference between sounds and words?
Well, here are some simple three-letter words of English.
We see in this data
that words are not holistic,
that there's a combinatorial system
that combines meaningless speech sounds,
yielding words with different meanings.
Now, there was an interesting discovery
way back in the 18th century
by a French priest, the Abbe de l'Epee, in Paris.
He discovered that the deaf people
in Paris, much to his surprise,
already had a language of their own
in which they could discuss any subject.
That was the beginning of recognition of sign languages
as a human means of communication.
American Sign Language, similarly,
it's indigenous to the deaf community here.
It's a mature sign language
that has been evolving for about 200 years,
and one of many structurally different
and mutually unintelligible sign language,
completely independent of English.
Most importantly, it has been shown
to have all the key properties
of spoken languages except speech.
A second and pivotal discovery came along
in a book by William Stokoe in 1960.
It has to do with, really,
what is the central point of my talk today,
which concerns the difference between gestures and signs.
He discovered that, like the words
of spoken languages, the signs of American Sign Language,
ASL, are not holistic, that there's a combinatorial system
that combines meaningless parts into meaningful signs.
I'll just show you what these are.
One component of signs is handshape.
This means change.
If I change the handshape from this to this,
it means translate.
If I change it to this, it means interpret.
Handshape is one of the components of signs.
A second is place of articulation.
This means bird, this means print,
and this means 20.
Same hand shape, same movement,
different places of articulation,
at the edge of the lip, or on the other hand,
or in neutral space before the signer.
Finally, movement is relevant.
This means name, this means short,
this means knife, and this means egg, okay?
All like so.
It's a combinatorial system.
Phonological, for spoken languages,
refers to the sound.
The same term is used for sign languages.
There's an inventory of handshapes,
places of articulation, and movements.
These are combined in different ways
to form different signs with different meanings.
Each sign consists of these components,
handshape, place of articulation, and movement.
There's also a fourth, orientation,
but I won't get into that today.
Now, we know what the difference is
between signs and gestures.
Signs, but not gestures, result from a combinatorial system
that takes these elements and combines them
to produce different signs with different meanings.
Here is bird again.
How do we know whether it is a sign or a gesture?
What characterizes it as a sign is,
it has these components,
the handshape, the L shape,
movement, the index touches the thumb twice,
and place of articulation is at the edge of the lip.
The handshape and movement exist in other signs.
Like I said before, 20, or print, or publish.
The edge of the lip is used in other signs
as place of articulation, like drink, or famous.
So the gestural hypothesis is
that what were originally gestures evolved over time
into signs in a combinatorial sign system,
each with its phonological representation,
which simply means, the same,
what the hand shape is, what the movement,
and what the place of articulation.
Important question, what would cause
a gestural communication system to evolve
into a combinatorial sign system?
The hypothesis I want to present today,
there are two things that would drive such an evolution.
The first is, you get clearer articulation
because, once you know you've got these three components,
each of which has, in other signs, a life of its own,
that limits how the signer can articulate the sign.
Second, that it makes it possible
for the relation between a sign's form
and its meaning to be completely arbitrary,
as in spoken languages.
This is a huge advantage because it makes possible
a vast increase in vocabulary size,
so that, in principle, there can be a sign for any meaning.
Those are the two things
that I'm proposing drive the evolution
from gestures to signs.
Now, as I said, we can't go back
to some original human language,
but we can observe, in a few rare cases,
the birth of a brand new manual communication system.
One such is in the Al-Sayyid Bedouin community
in southern Israel, studied by Sandler, Aronoff,
Meir, and Padden.
This is in a small, isolated Bedouin community
where, recently, there's been widespread deafness
in the community.
The spoken language is Arabic,
and the deaf people are using this new system,
and many of the hearing people as well,
because they have family, and siblings,
and so on, who are deaf.
This study started with a second generation of signers.
That is as close to the origin of languages
as one can get.
It's been developing there
with no contact with any other sign language.
What this team of researchers found is
that these people are, by the criteria
I've already laid out,
are using gestures, not signs,
that their words are holistic, not combinatorial,
so consequently, being not combinatorial,
I should really call a gesture,
each gesture is not analyzable into the parts
as the signs of sign languages are.
So there is a way that we can use this
to test some of our predictions.
Since a sign cannot be characterized
in terms of, this is its handshape,
this, its movement, this, its place of articulation,
then there's nothing to constrain the articulation.
What these researchers found was
that, in fact, the articulation is all over the place,
not just like limited differences
as you find in older languages,
like some people say economics
and some people say ee-conomics.
No, these are all over the place,
hardly recognizable in many cases.
There are big differences in pronunciation
from one family to another.
It's not as clear.
I have no real data on the size of the vocabulary,
but it's pretty clear that,
with this kind of total, all over the place articulation,
it can't be very big,
but I would hold that in an abeyance.
Certainly, the prediction of the proposal I made,
that getting a combinatorial system constrains articulation,
that comes out very nicely.
The next thing I want to mention
about the difference between gestures and signs is,
there was a lot of publicity for a long time
about chimpanzees supposedly learning sign language,
and the Gardners and Fouts signed
with their chimps for many years, and so on.
Rivas, 2005, studied 22 hours of video tapes,
eliminated imitations of what a caregiver had signed
in the previous five seconds,
and these are the results.
These four chimpanzees, the first number
is number of different so-called signs.
I'm claiming they were not signs, but gestures.
The four most frequent gestures by Washoe accounted
for 58% of his total production.
For Moja, the four most frequent accounted for 45%.
Tatu, 46%, Dar, 41%.
My conclusion is, especially if you compare
with the very large vocabularies of children
learning a spoken language,
conclusion, the chimpanzees learned no signs at all,
just a small set of holistic gestures.
Combinatoriality is widespread in language.
There's combinatorial morphology
that combines meaningful units,
word stems, prefixes, suffixes, into complex words.
We get complex words like undeniability,
and combinatorial syntax combines words
into phrases and sentences.
Combinatorial semantics combines the meanings
of smaller parts of sentences,
of words into phrases, phrases into sentences.
Consequently, combinatoriality characterizes human language
at every level.
We are a combinatorial species.
Thank you.
(audience claps)
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