The Proto-Sinaitic inscriptions consist of about forty individual inscriptions found at the Egyptian mining district at Serabit el-Khadem in the Sinai Peninsula. Along with the Wadi el-Ḥôl graffiti, they are some of the earliest alphabetic inscriptions ever discovered. For the most part, they date to the reigns of Amenemhet II (1831-1806 b.c.e) and Amenemhet III (1806-1777 b.c.e.) based on contextual evidence.
The Proto-Sinaitic inscriptions constitute important evidence for the genesis and development of alphabetic writing. The individual letters are generally pictographic and are based on hieroglyphic and hieratic models. Moreover, the selection of specific letters was based on the acrophonic principle, the idea that the value, shape, and name of individual letters are all related. The letter for b, for example, is shaped like a house (baytu). In the past, many scholars believed that the alphabet was invented at Serabit el-Khadem, but this view has fallen out of favor with the discovery of Wadi el-Ḥôl graffiti.
Hamilton, Gordon. The Origins of the West Semitic Alphabet in Egyptian Scripts. CBQMS 40. Washington D.C.: The Catholic Biblical Association of America, 2006).
Sass, Benjamin. The Genesis of the Alphabet and Its Development in the Second Millenium B. C. Ägypten und Altes Testament 13. Wiesbaden: Harrassowitz, 1988).