Maybe they will, I agree it is an integral part of the D&D 5e magic system along with somatics and spell components. Then again maybe the Psionic tadpoles forgo those needs.
Maybe for your party but I guess they'll be a bunch of enemy mages too, I agree with the op and adding voiced spellcasting is indeed lore/rule friendly (or even a must for the vocal component)
Also I think some animations should have a lot less cartoony/overly fantastic efects,such as dash and jump.
