So, I wanna ask how much verbal magic realistically needs to be taught versus an individual actively just practicing on their own to do their spells without saying anything? I say this because I just imagine Penelope would start heavily favoring not speaking while doing magic, but I don't wanna just hop into a class thread come September and be all like 'yep, this is how she does things'. I'd expect she's achieve class goals slower in a lot of her studies if she starts favoring this method at all, but I just wanna check if she'd be able to still do it?
Non-verbal magic is second only to wandless magic in difficulty, according to canon. Most characters graduate from Hogwarts sucking at it, if they can even do it at all.
I would wager that the British magical education system works like building a pyramid, with the base being the theory behind the spell, then the incantation, then the correct movement and intention. Until she's old enough to properly understand all three components, I don't think wordless magic would be an option for her (it's not taught until the NEWT level).
A case study:
tried non-verbal magic for five years and, even with extra help, still failed all of his practical classes in
his OWLs. xD