Olmec hieroglyphs

The Olmecs were the earliest known major Mesoamerican civilization, flourishing during the formative period (1500–400 BCE) in the tropical lowlands of the modern-day Mexican states of Veracruz and Tabasco.

(Skidmore 2007, p. 5)[4] All Mesoamerican writing systems feature toponyms,[5] i.e. "emblems or graphic images, which join distinct elements into meaningful arrangements but do not directly codify any specific set of sounds".

[6] These toponyms seem to have been employed in Olmec-style art since the Middle Formative period (900–500 BCE), but the degree to which they constitute writing (i.e., record spoken language) is debated.

These artifacts, dated roughly to 650 BCE (the middle of the Olmec concentration at La Venta and San Andres), were found in a refuse dump, the remains from a festival or feast.

“The fact that the artifacts with glyphs were found in the context of feasting refuse suggest that writing among the Olmec was sacred and was closely tied to ritual activities.” [19] The most important find was a fist-sized ceramic cylinder seal, likely used to print cloth.

When rolled out, the seal shows two speech scrolls emanating from a bird, followed directly by a number of design elements enframing what has been interpreted as logograms for “king (sideways U shape),” "3 (three dots, according to the Mesoamerican bar and dots numbering system),” and “Ajaw (from the sacred 260-day calendar)", a designation used for both a calendar date and, in keeping with Mesoamerican custom, the name of an Olmec ruler.

The 28 unique Cascajal block characters bear no obvious resemblance to the San Andres glyphs and are, indeed, unlike those of any other Mesoamerican writing system.

The following year, however, their interpretation was disputed by Stephen Houston and Michael D. Coe, who unsuccessfully applied Justeson and Kaufman's decipherment system against Epi-Olmec script from the back of a hitherto unknown mask.