Indus script encodes
language, reveals new study of ancient symbols
Thursday, April 23,
2009
Examples of the Indus script. The four square artifacts with
animal and human iconography are stamp seals that measure one or
two inches per side. On the top right are three elongated seals
that have no iconography, as well as three miniature tablets (one
twisted). The tablets measure about 1.25" long by 0.5" wide.
Credit: J.M. Kenoyer/Harappa.com
The Rosetta Stone allowed 19th
century scholars to translate symbols left by an ancient
civilization and thus decipher the meaning of Egyptian
hieroglyphics.
But the symbols found on many other ancient artifacts remain a
mystery, including those of a people that inhabited the Indus
valley on the present-day border between Pakistan and India. Some
experts question whether the symbols represent a language at all,
or are merely pictograms that bear no relation to the language
spoken by their creators.
A University of Washington computer scientist has led a statistical
study of the Indus script, comparing the pattern of symbols to
various linguistic scripts and nonlinguistic systems, including DNA
and a computer programming language. The results, published online
Thursday by the journal Science, found the Indus script's pattern
is closer to that of spoken words, supporting the hypothesis that
it codes for an as-yet-unknown language.
"We applied techniques of computer science, specifically machine
learning, to an ancient problem," said Rajesh Rao, a UW associate
professor of computer science and engineering and lead author of
the study. "At this point we can say that the Indus script seems to
have statistical regularities that are in line with natural
languages."
Co-authors are Nisha Yadav and Mayank Vahia at the Tata Institute
of Fundamental Research in Mumbai, India; Hrishikesh Joglekar, a
software engineer from Mumbai; R. Adhikari at the Institute of
Mathematical Sciences in Chennai, India; and Iravatham Mahadevan at
the Indus Research Center in Chennai. The research was supported by
the Packard Foundation and the Sir Jamsetji Tata Trust.
The Indus people were contemporaries of the Egyptian and
Mesopotamian civilizations, inhabiting the Indus river valley in
present-day eastern Pakistan and northwestern India from about 2600
to 1900 B.C. This was an advanced, urbanized civilization that left
written symbols on tiny stamp seals, amulets, ceramic objects and
small tablets.
"The Indus script has been known for almost 130 years," said Rao,
an Indian native with a longtime personal interest in the subject.
"Despite more than 100 attempts, it has not yet been deciphered.
The underlying assumption has always been that the script encodes
language."
In 2004 a provocative paper titled The Collapse of the Indus-Script
Thesis claimed that the short inscriptions have no linguistic
content and are merely brief pictograms depicting religious or
political symbols. That paper's lead author offered a $10,000
reward to anybody who could produce an Indus artifact with more
than 50 symbols.
Taking a scientific approach, the U.S.-Indian team of computer
scientists and mathematicians looked at the statistical patterns in
sequences of Indus symbols. They calculated the amount of
randomness allowed in choosing the next symbol in a sequence. Some
nonlinguistic systems display a random pattern, while others, such
as pictures that represent deities, follow a strict order that
reflects some underlying hierarchy. Spoken languages tend to fall
between the two extremes, incorporating some order as well as some
flexibility.
The new study compared a well-known compilation of Indus texts with
linguistic and nonlinguistic samples. The researchers performed
calculations on present-day texts of English; texts of the Sumerian
language spoken in Mesopotamia during the time of the Indus
civilization; texts in Old Tamil, a Dravidian language originating
in southern India that some scholars have hypothesized is related
to the Indus script; and ancient Sanskrit, one of the earliest
members of the Indo-European language family. In each case the
authors calculated the conditional entropy, or randomness, of the
symbols' order.
They then repeated the calculations for samples of symbols that are
not spoken languages: one in which the placement of symbols was
completely random; another in which the placement of symbols
followed a strict hierarchy; DNA sequences from the human genome;
bacterial protein sequences; and an artificially created linguistic
system, the computer programming language Fortran.
Results showed that the Indus inscriptions fell in the middle of
the spoken languages and differed from any of the nonlinguistic
systems.
"We would like to make as much headway as possible and ideally,
yes, we'd like to crack the code," Rao said. "For now we want to
analyze the structure and syntax of the script and infer its
grammatical rules. Someday we could leverage this information to
get to a decipherment, if, for example, an Indus equivalent of the
Rosetta Stone is unearthed in the future."
###
University of Washington
Thanks to University of Washington
for this article.