Earliest abecedary ever?

SOMETHING LIKE THAT: The earliest known abecedary (PhysOrg). But this is not the abecedary known and used today in the English and other alphabers — the one that begins a-b-c:

A flake of limestone (ostracon) inscribed with an ancient Egyptian word list of the fifteenth century BC turns out to be the world's oldest known abecedary. The words have been arranged according to their initial sounds, and the order followed here is one that is still known today. This discovery by Ben Haring (Leiden University) with funding from Free Competition Humanities has been published in the October issue of the Journal of Near Eastern Studies.

The order is not the ABC of modern western alphabets, but Halaḥam (HLḤM), the order known from the Ancient Egyptian, Ancient Arabian and Classical Ethiopian scripts. ABC and HLḤM were both used in Syria in the thirteenth century BC: cuneiform tablets found at site of ancient Ugarit show both sequences. Back then, ABC was still '-b-g ('aleph-beth-gimel). This sequence was favored by the Phoenicians who passed it on to the Greeks, together with the alphabet itself. Thus a-b-g found its way to the later alphabets inspired by the Greek and Latin ones.

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You can read the JNES article by Ben Haring at JSTOR: Halaḥam on an Ostracon of the Early New Kingdom? But notice that the article ends with a question mark, which is why my title above does likewise. Not mentioned in the PhyOrg article is that parts of the rest of the sequence of sounds are preserved on the ostracon and they correspond only in a vague way to the traditional Halaḥam alphabetic sequence. So the case is not airtight, although it does seem quite likely that this is an early and fluid example of what eventually would become a fixed sequence of sounds and letters.