A recent article publicizes the theory of Douglas Petrovich's theory that Hebrews invented the alphabet. Petrovich claims to identify new letters on inscriptions from Egypt and read them as Hebrew, from which he argues that the Hebrews invented the alphabet. Such a theory has been argued before, but it is interesting to see such a theory revived here.
It's fairly well-established that Egyptian hieroglyphs were adapted into an alphabet to write a Semitic language at an early period. What is most problematic is identifying which Semitic language. We know precious little about the earliest stages of the Northwest Semitic languages, and the language boundaries we are so used to thinking about in later periods do not easily fit the oldest evidence. I heard Petrovich give the same paper last year, and the examples he showed did not strike me as good evidence for identifying them as Hebrew as distinct from other Canaanite languages/dialects. Many of his identifications and translations seemed highly questionable; neither were they really distinctive of Hebrew. I'm willing to give him a hearing, but I remain very skeptical that he will be able to make this case in a compelling manner.
Update: Similar, but more detailed, thoughts from Christopher Rollston on the early Semitic inscriptions.