This study conducts an epigraphic analysis of the yet undeciphered inscriptions of the ancient Indus Valley civilization and seeks to prove that just like proto-cuneiform administrative tablets of ancient Mesopotamia, or modern fiscal stamps and ration tokens, Indus seals and tablets too were formalized data-carriers that used both document-specific and linguistic syntaxes to convey messages. Analyzing various combinatorial patterns of Indus signs (e.g., typical co-occurrence restrictions present between some signs; tendency of some signs to form collocations; syntactic order(s) maintained between certain signs; strong positional preferences demonstrated by some signs; and the capability of certain signs to occur alone in inscriptions), this paper argues that Indus signs represented different content-morphemes and functional-morphemes—not phonograms used for spelling words—the majority of the inscriptions were logographic. Categorizing several Indus logograms into nine functional classes, it explores the way each sign-class has played unique functional roles for conveying complete messages through the brief inscriptions. By glossing the signs of the inscriptions using the names of their respective functional classes the study unravels the formulaic phrase-structures maintained by the majority of the inscriptions, where signs identified as phrase-final signs typically occur at the terminal positions of the semantic phrases, while signs used as connective-morphemes join semantically autonomous constituents in certain subordinating and coordinating ways, to form longer composite inscriptions.

The study identifies certain Indus signs as numerical and metrological signs, which frequently collocate with specific lexemes, and clearly quantifying them in certain ways. This article also analyses the underlying relationships between certain metrological and phrase-final signs; examines the compositional nature of Indus collocations; and argues that some of the repeated sign-sequences were probable examples of linguistic reduplication. Analyzing the occasional occurrences of certain attributive quantifier signs as substantive lexemes, this paper suggests that in some inscriptional contexts those quantifier signs possibly represented certain commonly used metonyms of Indus civilization. Finally, this study explores the compositional semantics of Indus inscriptions without assigning any sound value to the signs and without speculating about whether the script encoded the speech of any specific ancient language.