We can ask if the script is logo-syllabic (in which the signs represent complete words or syllables), syllabic (in which the signs almost exclu- sively have a syllabic value), or alphabetic (in which the signs represent separate phonemes, in the oldest scripts of this type mainly conso- nants)? The main criteria that can be used to define the type are the number of distinct signs, the word length measured in the number of signs, and the age of the script.
In the Indus script, the number of known signs is around 400, with about 200 basic elements. This number corresponds fairly well to the number actively used in logo-syllabic scripts at one time; it is too high for the script to be syllabic or alphabetic. Word divisions are not marked, but there is a good number of inscriptions comprising only one, two or three signs, and many of the longer ones can be subdivided into such units. In logo-syllabic scripts, one to three signs is a very typical word length, but in syllabic and alphabetic scripts, many words are much longer.
As to the age of the Indus script, the Mature Harappan phase, in which the fully developed Indus script was used, is assumed to have started between 2600–2500 BCE. A baked seal impression and a pot- sherd with short inscriptions that include the most frequently attested sign of the Indus script were recently excavated at Harappa. They suggest that the Indus script was created during the last phase of the Early Harappan period, between 2800–2600 BCE. Inspiration, restricted to the basic principle of logo-syllabic writing, is likely to have come from the Proto-Elamite script (c. 3100–2900 BCE), which was widely used on the Iranian Plateau.33) The creators of the Indus script seem to have mainly resorted to traditional local symbols of the Greater Indus Valley.
The Indus script is thus much older than the earliest known syllabic scripts, the Eblaite cuneiform of Syria and the Linear Elamite of Susa, which date from around 2350 and 2250 BCE respectively. The earliest
______________________________ 33) Cf. Driem 2001: II, 998–1000.
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