How did pictographs in Sumerian writing become cuneiform signs?

The transition from pictographs to cuneiform in the Sumerian language was a gradual process driven by both functional needs and the physical constraints of the writing medium.

Initially, Sumerian writing consisted of pictographic tablets used for bookkeeping, where drawings represented concrete objects. As the system evolved, these pictographs became increasingly conventionalized and cursive. The shift to "cuneiform" (from the Latin cuneus, meaning "wedge") occurred primarily because scribes began using a blunt stylus to press into soft clay rather than drawing with a pointed stick. This technique transformed curved lines into distinct, wedge-shaped strokes.12

This evolution was accompanied by two major developments:
* Phoneticization: To express abstract concepts or proper names, the rebus principle was adopted, where signs represented sounds rather than just the objects depicted.12
* Standardization: Over time, the orientation of signs was fixed, and the script moved from columns running downward to a left-to-right horizontal flow, which required turning the signs on their sides.1