They had coinage with Greek writing in some periods, as I mentioned, which implies that Greeks must have had a very large influence on Aksum. It was only centuries later that they switched to non-Greek, native writing, possibly around the decline of Aksum.
> The Periplus of the Erythraean Sea mentions that the Aksumite state imported brass (Ancient Greek: ὀρείχαλκος, oreíkhalkos), "which they use[d] for ornaments and for cutting as money", and they imported "a little money (denarion) for [use by] foreigners who live there."
https://en.wikipedia.org/wiki/Endybis
https://en.wikipedia.org/wiki/Aksumite_currency
> The Periplus of the Erythraean Sea mentions that the Aksumite state imported brass (Ancient Greek: ὀρείχαλκος, oreíkhalkos), "which they use[d] for ornaments and for cutting as money", and they imported "a little money (denarion) for [use by] foreigners who live there."
https://en.wikipedia.org/wiki/Kingdom_of_Aksum
> Aksum also had a sizeable Greek population, which resided in the cities of Ptolemais Theron and Adulis.[52]