system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Do non-verbal spells still require some sort of hand or wand movement?

Like if I somehow tied up Voldemort and gagged him would I still be susceptible to spells from him?
gpt
It depends on the skill and magical merit.

Expert tier wizards can both *wandlessly* and *non-verbally* cast spells, but it takes a lot of mental willpower and multitask abilities, which is why non-verbal magic is not taught until 6th year in Hogwarts.

For instance, during the duel between Dumbledore and Voldemort, he casted a Fiendfyre and manipulated it into a giant serpent. He did it non-verbally and wandlessly. And Fiendfyre is one of the most difficult, elaborate and delicate curses that exist, hell, Hermione was afraid to cast the curse (even though it's one of the few spells which can destroy a Horcrux). That alone demonstrates the apex of Voldemort's powers.

Yes, it's possible to not make any hand movements or use a wand at all. African wizarding school also teaches wandless magic use more prominently than Hogwarts, as a wand was an European invention.