Decipherability The following factors are usually regarded as the biggest obstacles to successful decipherment: • Inscriptions are very short. The average length of the inscriptions is around five signs,. Inscriptions vary between just one and seven lines, with single lines being the most common. • There are doubts whether the Indus script records a written language or is instead a system of non-linguistic signs or
proto-writing similar to
merchant's marks and
house marks, and to the contemporary
accounting tokens and
numerical clay tablets of Mesopotamia. Due to the brevity of inscriptions, some researchers have questioned whether Indus symbols can even express a spoken language. • Even when interpreted as written language, it is unknown whether each sign generally represents a whole word, part of a word (such as a
morpheme or syllable), or part of a sentence. • The spoken
Harappan language has not been identified, so, assuming the script is a written language, the language the script is most likely to express is unknown. However, an estimated 300 loanwords in the
Rigveda may provide evidence of
substrate language(s) which may have been spoken in the region of the
Indus civilisation. • No
digraphic or
bilingual texts, like the
Rosetta Stone, have been found. • No names, such as those of Indus rulers or personages, are known to be attested in surviving historical records or myths, as was the case with rulers like Rameses and Ptolemy, who were known to
hieroglyphic decipherers from records attested in Greek. Over the years, numerous decipherments have been proposed, but there is no established scholarly consensus. The few points on which there exists scholarly consensus are the right-to-left direction of the majority of the inscriptions, numerical nature of certain stroke-like signs, functional homogeneity of certain terminal signs, and some generally adopted techniques of segmenting the inscriptions into initial, medial, and terminal clusters. Over 100 (mutually exclusive) attempts at decipherment have been published since the 1920s, and the topic is popular among amateur researchers. In 2025, Tamil Nadu Chief Minister
M. K. Stalin announced a $1 million (USD) prize for deciphering the Indus Valley Script, stating that "Archaeologists, Tamil computer software experts and computer experts across the world have been making efforts to decipher the script but it remains a mystery even after 100 years."
Dravidian language , meaning "star", per the
rebus principle in the context of some Indus inscriptions Although no clear consensus has been established, there are those who argue that the Indus script recorded an early form of the
Dravidian languages (
Proto-Dravidian). Early proponents included the archaeologist
Henry Heras, who suggested several readings of signs based on a
proto-Dravidian assumption. Based on computer analysis, the Russian scholar
Yuri Knorozov suggested that a Dravidian language is the most likely candidate for the underlying language of the script. The Finnish scholar
Asko Parpola led a Finnish team in the 1960s–80s that, like Knorozov's
Soviet team, worked toward investigating the inscriptions using computer analysis. Parpola similarly concluded that the Indus script and Harappan language "most likely belonged to the Dravidian family". A comprehensive description of Parpola's work up to 1994 is given in his book
Deciphering the Indus Script. Supporting this work, the archaeologist
Walter Fairservis argued that Indus script text on seals could be read as names, titles, or occupations, and suggested that the animals depicted were
totems indicating
kinship or possibly
clans. The computational linguist
Rajesh P. N. Rao, along with a team of colleagues, performed an independent computational analysis and concluded that the Indus script has the structure of a written language, supporting prior evidence for
syntactic structure in the Indus script, and noting that the Indus script appears to have a similar
conditional entropy to
Old Tamil. These scholars have proposed readings of many signs; one such reading was legitimised when the Dravidian
homophonous words for 'fish' and 'star', , were hinted at through drawings of both the things together on Harappan seals. In a 2011 speech, Rajesh P. N. Rao said that
Iravatham Mahadevan and Asko Parpola "have been making some headway on this particular problem", namely deciphering the Indus script, but concluded that their proposed readings, although they make sense, are not yet proof. (). In his 2014 publication
Dravidian Proof of the Indus Script via The Rig Veda: A Case Study, the epigraphist Iravatham Mahadevan identified a recurring sequence of four signs which he interpreted as an early Dravidian phrase translated as "Merchant of the City". Commenting on his 2014 publication, he stressed that he had not fully deciphered the Indus script, although he felt his effort had "attained the level of proof" with regard to demonstrating that the Indus script was a Dravidian written language.
Non-Dravidian languages Indo-Aryan language Perhaps the most influential proponent of the hypothesis that the Indus script records an early
Indo-Aryan language is the Indian archaeologist
Shikaripura Ranganatha Rao, who in his books,
Lothal and the Indus Civilization (1973) and
The Decipherment of the Indus Script, wrote that he had deciphered the script. While dismissing most such attempts at decipherment, John E. Mitchiner commented that "a more soundly-based but still greatly subjective and unconvincing attempt to discern an
Indo-European basis in the script has been that of Rao". S. R. Rao perceived a number of similarities in shape and form between the late Harappan characters and the Phoenician letters, and argued that the Phoenician script evolved from the Harappan script, and not, as the classical theory suggests from the
Proto-Sinaitic script. He compared it to the
Phoenician alphabet, and assigned sound values based on this comparison. Reading the script from left to right, as is the case with Brahmi, he concluded that Indus inscriptions included numerals and were "
Sanskritic". S. R. Rao's interpretation helped to bolster
Hindu nationalist and
Aryan indigenist views propagated by writers, such as
David Frawley, who hold the conviction that
Indo-Aryan peoples are the original Bronze Age inhabitants of the
Indian subcontinent and that the
Indo-European language family originated in India. However, there are many problems with this hypothesis, particularly the cultural differences evident between the Indus River Civilisation and
Indo-European cultures, such as the role of horses in the latter; as Parpola put it, "there is no escape from the fact that the horse played a central role in the Vedic and Iranian cultures". Additionally, the Indus script appears to lack evidence of
affixes or
inflectional endings, which Possehl has argued rules out an Indo-European language such as Sanskrit as the language of the Indus script.
Munda language A less popular hypothesis suggests that the Indus script belongs to the
Munda family of languages. This language family is spoken largely in central and eastern India, and is related to some Southeast Asian languages. However, much like the Indo-Aryan language, the reconstructed vocabulary of early Munda does not reflect the Harappan culture, therefore, its candidacy for being the language of the Indus Civilisation is dim.
Non-linguistic signs , Indus Valley , dubbed the
Dholavira Signboard An opposing hypothesis is that these symbols are nonlinguistic signs which symbolise families, clans, gods, and religious concepts, and are similar to components of
coats of arms or
totem poles. In a 2004 article, Steve Farmer,
Richard Sproat, and
Michael Witzel presented a number of arguments stating that the Indus script is nonlinguistic. The main ones are the extreme brevity of the inscriptions, the existence of too many rare signs (which increase over the 700-year period of the Mature Harappan civilisation), and the lack of the random-looking sign repetition that is typical of language.
Asko Parpola, reviewing the Farmer
et al. thesis in 2005, stated that their arguments "can be easily controverted". He cited the presence of a large number of rare signs in Chinese and emphasised there was "little reason for sign repetition in short seal texts written in an early logo-syllabic script". Revisiting the question in a 2008 lecture, Parpola took on each of the 10 main arguments of Farmer
et al., presenting counterarguments for each. A 2009 paper published by
Rajesh P. N. Rao,
Iravatham Mahadevan, and others in the journal
Science also challenged the argument that the Indus script might have been a nonlinguistic symbol system. The paper concluded the
conditional entropy of Indus inscriptions closely matched those of linguistic systems like the Sumerian logo-syllabic system, Rig Vedic Sanskrit etc., but they are careful to stress that by itself does not imply the script is linguistic. A follow-up study presented further evidence in terms of entropies of longer sequences of symbols beyond pairs. However, Sproat argued there existed a number of misunderstandings in Rao
et al., including a lack of discriminative power in their model, and argued that applying their model to known non-linguistic systems such as Mesopotamian deity symbols produced similar results to the Indus script. Rao
et al. argument against Sproat's arguments and Sproat's reply were published in
Computational Linguistics in December 2010. The June 2014 issue of
Language carries a paper by Sproat that provides further evidence that the methodology of Rao
et al. is flawed. Rao
et al. rebuttal of Sproat's 2014 article and Sproat's response are published in the December 2015 issue of
Language. ==Unicode==