After Link first encounters the Skullkid, he is transformed into a Deku scrub. 
In this form, he has no weapons (save for the Power of bubbles), and is far more vulnerable in every sense of this world. This makes even the hero of time a bit twitchy and nervous, tripping over his words and stuttering frequently. But even in a weaker form, Link still perseveres with courage and heart, searching for a way to return to normal. As an inhuman creature, Deku Link's voice is inhumanly high and nasally, much more so than his regular voice. I am alright with voices being pitched up a bit to meet these standards, but not so much that it's overtly obvious.