spellcasting while disguised

[Akai]

I've heard that on Avlis there's a rule that one cannot cast spells using a disguised voice (though Silent Spell makes that irrelevant when used). What about here, is it possible to cast spells in an accent/intonation/pitch different from one's normal spellcasting technique? If it were attempted, would it be unrecognizable as the same spellcaster? would it sound similar but with notable differences? Would some skill roll be appropriate to determine the success of the voice alteration?

[Psye Shaar]

Spells are cast in the characters normal voice due to the intricacies and exact pronunciation required to get the spell correct.

For anyone that wishes to cast while disguised, they need to invest in silent spell to remain anonymous, otherwise anyone that knows their voice well enough will recognise them.

Emoting a disguised voice is not sufficient.