Late Bronze Age collapse
According to the "alphabet theory", the early Semitic proto-alphabet reflected in the proto-Sinaitic inscriptions would have given rise to both the Ancient South Arabian script and the Proto-Canaanite alphabet by the time of the Late Bronze Age collapse (1200–1150 BCE). Albright hypothesized that only the graphic form of the proto-Sinaitic characters derive from Egyptian hieroglyphs, because they were given the sound value of the first consonant of the Semitic translation of the hieroglyph (many hieroglyphs had already been used acrophonically in Egyptian.)