So i looked it up and at least the Emotional Song Pact seems like a mix of Greek and latin https://artonelico.fandom.com/wiki/Emotional_Song_Pact
Looks how some look like Α Θ ξ Ξ Γ Ν Τ ε Ζ (from greek) and L C ? 7 S from latin
while the "each letter represents a syllable" reminds of the...