[SmG Battlefire]

There are also something called Nonverbal Spells. A way to not give out warning on what spell you are going to use. Harry used the Levicorpus and the Liberacorpus spell. And here is a catch he didn't use his wand. When he used the Liberacorpus on Ron, he used his hands. The Levicorpus was though his mind.

Edit: Also Hermione has the most accounts of Wandless spells and Nonverbal spells. Which makes sense because she is the brightest student in Hogwarts. But during their escape from the Ministry of Magic. Hermione did teach Ron and Harry useful spells.