In the short story "The Lottery in Babylon", Jorge Luis Borges describes an imaginary society where a Lottery decides the fate of the people, with omnipotence and foresight. At the beginning of the original text we read
[ES] Miren: por este desgarrón de la capa se ve en mi estómago un tatuaje bermejo: es el segundo símbolo, Beth. Esta letra, en las noches de luna llena, me confiere poder sobre los hombres cuya marca es Ghimel, pero me subordina a los de Aleph, que en las noches sin luna deben obediencia a los Ghimel.
and in English:
[EN] Look: through this rent cape can be seen on my stomach a ruddy tattoo — it is the second symbol, Beth. On nights when the moon is full, this symbol confers unto me power over the men whose mark is Ghimel while rendering me subject to the men of Aleph, who on moonless nights must obey the men of Ghimel.
Since I first read this novel, I have been convinced that the sequence "aleph, beth, gimel" is the beginning of the Hebrew alphabet. Now I'm not sure any more, as the second letter is called "Bet", not "Beth".
So, if not Hebrew, what is the alphabet that the proconsul in Babylon is referring to?