Thirty incised graffiti in a "Proto-Sinaitic script" shed light on the history of the alphabet. The mines were worked by prisoners of war from southwest Asia who presumably spoke a Northwest Semitic language, such as the Canaanite that was ancestral to Phoenician and Hebrew. After a century of study and the initial publication by Sir Flinders Petrie, researchers agree on the decipherment of a single phrase, cracked in 1916 by Alan Gardiner: לבעלת l bʿlt , although the wordm’hb is frequently cited as a second word. The script has graphic similarities with the Egyptian hieratic script, the less elaborate form of the hieroglyphs. In the 1950s and 1960s it was common to show the derivation of the Canaanite alphabet from hieratic, using William Albright's interpretations of Proto-Sinaitic as the key. It was generally accepted that the language of the inscriptions was Semitic, that the script had a hieratic prototype and was ancestral to the Semitic alphabets, and that the script was itself acrophonic and alphabetic. The word baʿlat lends credence to the identification of the language as Semitic. However, the lack of further progress in decipherment casts doubt over the other suppositions, and the identification of the hieratic prototypes remains speculative. Romanus Francois Butin of Catholic University of America published articles in the Harvard Theological Review based on the 1927 Harvard Mission to Serabit and the 1930 Harvard-Catholic University Joint Expedition. His article "The Serabit Inscriptions: II. The Decipherment and Significance of the Inscriptions" provides an early detailed study of the inscriptions and some dozen B/W photographs, hand-drawings and analysis of the previously published inscriptions, #346, 349, 350-354, and three new inscriptions, #355-368. At that time, #355 was still in situ at Serabit but had not been photographed by the previous Harvard Mission. In 1932, he wrote: "The present article was begun with the limited purpose of making known the new inscriptions discovered by the Harvard-Catholic University Joint Expedition to Serabit in the spring of 1930. In the course of this study, I perceived that some signs doubtful in the inscriptions already published were made clear by the new slabs, and I decided to go over the entire field again." Both articles provide an analysis of the Proto-Sinaitic inscriptions during earlier expeditions to the site.
In her book A History of Sinai, Lina Eckenstein theorized that Serabit el-Khadim was the historical site of Mt. Sinai where Moses received the Ten Commandments. This theory comes in no small part to the site containing a temple of Hathor, the goddess Eckenstein believed was represented by the idol of a golden calf constructed by the Hebrews while Moses was on the mountain top.
