Editing Indus script (section)

===Non-linguistic signs===
[[File:Indus script recovered from Khirsara, Indus Valley Civilization.jpg|thumb|upright=1.5|Indus script tablet recovered from [[Khirasara]], Indus Valley]]
[[File:The 'Ten Indus Scripts' discovered near the northen gateway of the citadel Dholavira.svg|thumb|upright=1.5|A sequence of Indus characters from the northern gate of [[Dholavira]], 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 [[coat of arms|coats of arms]] or [[totem pole]]s. In a 2004 article, Steve Farmer, [[Richard Sproat]], and [[Michael Witzel]] presented a number of arguments stating that the Indus script is nonlinguistic.{{sfnp|Farmer|Sproat|Witzel|2004}} 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.{{sfnp|Lawler|2004}}

[[Asko Parpola]], reviewing the Farmer ''et al.'' thesis in 2005, stated that their arguments "can be easily controverted".{{sfnp|Parpola|2005|p=37}} 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,{{sfnp|Parpola|2008}} Parpola took on each of the 10 main arguments of Farmer ''et al.'', presenting counterarguments for each.

A 2009 paper{{sfnp|Rao|Yadav|Vahia|Joglekar|2009}} published by [[Rajesh P.&nbsp;N. Rao]], [[Iravatham Mahadevan]], and others in the journal ''[[Science (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.{{sfnp|Rao|2010}} 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.''{{'s}} argument against Sproat's arguments and Sproat's reply were published in ''[[Computational Linguistics (journal)|Computational Linguistics]]'' in December 2010.<ref>[http://www.mitpressjournals.org/toc/coli/36/4 Computational Linguistics], Volume 36, Issue 4, December 2010.</ref>{{sfnp|Rao|Yadav|Vahia|Joglekar|2010}} The June 2014 issue of [[Language (journal)|''Language'']] carries a paper by Sproat that provides further evidence that the methodology of Rao ''et al.'' is flawed.{{sfnp|Sproat|2014}} Rao ''et al.''{{'s}} rebuttal of Sproat's 2014 article and Sproat's response are published in the December 2015 issue of ''Language''.{{sfnp|Rao|Yadav|Vahia|Jonathan|2015}}{{sfnp|Sproat|2015}}